It's late and I'm not going to go out to the bench to pull my spare parts and start comparing them to the ones in my own 3rd gen .45's, but here's a couple thoughts to mull over.
In my first armorer class we were told the "gap" between the
outside of the frame and the
inside of the slide stop's lever ought to be such that a normal business card can slip under it, or even a folded (once) business card. Ideally, the gap ought to be uniform from front to back.
If a lever were to become too "tight" against the frame at the rear, the lever could drag on the frame and possibly interfere with the lever's freedom of movement.
Some occasional drag marks on a particular frame were said to be considered normal, and only cosmetic, if a lever's angle was on the tighter end of the normal tolerance range, as long as the lever's gap (with the frame) was even and the lever wasn't prevented from lifting when lifted by the mag follower, and would be pushed downward by normal tension between the front of the sideplate and the lever's plunger/spring (to prevent it from rising under recoil and causing early slide lock).
Too wide of a gap from the frame, though, and at some point the lever's plunger might jump outward, slipping off the outside of the sideplate. (Meaning the small angled plate formed at the front of the sideplate.)
The gap in one of your pics looks a bit wide (but it's just a pic, and I couldn't pretend to know without handling it and seeing it).
How can a slide stop lever become bent? Well, recoil forces travel through metal in all directions, and we were told that it was sometimes possible that a
lot of use, and hot ammo, might sometimes cause a slide stop lever to eventually acquire an
inward or outward bend. (This presumes someone hasn't actually damaged it, meaning bending it.)
The angle between the slide stop's lever and its (frame) pin ought to be 90 degrees. (Looking "down" on it, as it were.)
In my first 3rd gen armorer class we were told to keep an eye on the gap between the slide stop lever and frame, especially if we were shooting a lot of +P or +P+ loads (the discussion was about the 59XX series guns). If we came across a lever that had acquired an excessive inward or outward bend, we were shown how to put the lever assembly in a vise and whack it with a
lead babbitt (NOT a hammer) to restore the 90 degree angle.
In subsequent classes that was changed to telling armorers to just replace a slide stop lever assembly that had acquired a bend. Reading between the lines, perhaps over time some slide stop assemblies ended up being needlessly (or simply improperly) beaten and mangled by inexperienced armorers, so the armorer training folks decided to simplify things and just tell armorers to replace them. (Ditto replacing the lever assembly if a lever's plunger and spring if they became damaged or corroded, while previously we'd been told to just drift the roll pin and replace a plunger and spring, and the plunger could be different, especially in the .40's.)
Now, the
outside edge of the front curved shoulder of your slide stop lever almost appears peened and rolled over. See the normal clean and sharp line on the outside edge of the part of the slide stop in this image, in the circle?
That raised curved spot on the front of the lever rides on the inside of the lower edge of the slide and prevents the slide stop from drifting out of the frame unless the slide is retracted to the point where the slide stop can then clear the slide's notch (for disassembly). The 2 pics in your first post makes it appear badly peened.
How might that happen? Dunno. However, I'd almost wonder if a previous owner might not have known how to properly field-strip the gun, meaning he didn't properly position the front of the lever assembly within the slide's notch, and out of frustration he used heavy force (beat) on the right end of the pin, trying to move the assembly to the left to remove the slide stop.
Also, if you gently grasp the front angled plate of the sideplate between your thumb and index finger, can you gently wiggle it up and down? If it moves (more than a minimal amount, or a "hair"), it might be involved. This can mean one of the "prongs" of the sideplate's fork, which snap over the left (headed) end on the sear pin, is bent or snapped off. Time for a new sideplate.
The .45 slide stop levers made toward the end of 3rd gen production were either plain stainless, or blackened stainless (machined MIM) parts, if I remember right. They ought not need any "adjustment", and are considered "drop-in" assemblies, presuming they aren't damaged or out-of-spec, and if they function in the particular gun as intended when doing normal bench checks. (Sometimes in 'parts-is-parts' guns a particular part or assembly might not work normally in one gun, but might in many others.)
Oh yeah, don't go yanking on the plunger of the older 'staked' guide rods.
The plunger and spring could be easily removed from the newer style, 1-piece rods, but the old style 'staked' rods had a collar (staked to the rod) which contained the plunger and spring in the rod. Damage an earlier staked collar and it's time for a new rod assembly.
These pics show the difference in the older and the newer revised rod assemblies.
New rod on left, 2 older rods in middle and on right.
2 new style rods (different models/finishes), and this pic also has a plastic plunger used in some models for a while.
Sorry for the rambling, but these were just some late night thoughts in response to the thread. I'll try and check back tomorrow.
FWIW, now that the 3rd gen's have reached "obsolete" status, it's getting harder to find new parts, although it's apparently possible to find them now and again.