Hi Rifleman762,
Since your gun is equipped with the nested spring assembly it should have a small reducing bushing installed in the slide's spring tunnel from the inside.
That bushing removed looks like this:
If your gun lacks that bushing, I'd venture the nested spring set is not original to that arm. The 4516-1 version typically is seen with a 0.290" diameter aluminum guiderod and a single 20 coil 16lb spring. That nested spring setup with the 0.236" solid stainless guiderod applies to all the other 4516 variants (4516no dash, 4516-2 & -3)
I'd not run the gun in that condition. The concern here is under firing stresses the end coil of the inner spring could work it's way into the gap around the guiderod and tie up the gun.
There are a few ways to fix your issue here....
You can have a bushing made to fit the slide and the skinny guiderod then stay with the nested spring set. Anyone with some skill and a metal lathe can make one of those bushings in mere minutes.
or...
Install a flatwire spring on the skinny guiderod in place of the nested springs. I run one of these springs in my 4516-1:
ISMI Glock Compact 20lb Recoil Spring G19,23,25,32,38
or...
Restore to factory condition. You'll need a 4516-1 guiderod and the single coil spring. S&W no longer produces either of these parts. However, Wolff makes single springs in a variety of weights for that gun. And, it just so happens I have a couple of those old guiderods to spare if you can't find one.
Strickly speaking of reliable functioning and your agency policy of factory parts notwithstanding I'd go with the flatwire spring.
If we want reliability and complaince with the factory parts policy, have someone make a bushing for that gun and stay with the nested spring set.
Oh and your sideplate is just plain broke. The hammer pin should be permanently affixed. The good news is you can use just about any sideplate from any large frame 3rd gen gun. Any 45xx or 10xx or even a black one from a 457 will work. The prefered part though is the 108600000 R1 or revision 1 which reinforced the attachment of the hammer pin to the plate. However, the 106990000 is dimensionally identical and will fit just fine. I have that part installed in two of my guns.
Cheers
Bill