"Red Flag"?!?
Relax, folks.
Yes, S&W introduced a polymer guide rod plunger for some of the budget models, including the CS guns. Just like they designed polymer disconnectors and mainspring cups in the 90's ... and don't forget the long running ejector depressor plunger.
Back when I first noticed I had a polymer guide rod plunger in my CS45 (bought '99 or 2000?), I called and asked about it with one of the guys at the factory. He said they weren't getting complaints about them in Pistol Repair, but offered to send me a few extra stainless steel plungers if I wanted. Why not, right?
After fiddling with the polymer and the stainless plungers in my CS45 (and later CS9), both of my CS guns are running ... polymer guide rod plungers.
Yes, I noticed some minor abrading and light fuzz at the end of the polymer plungers, similar to what was seem in the video. I just removed it (cut or plucked, depending), and didn't worry about it anymore.
FWIW, I also started letting my recoil springs run out a little longer in the CS45/9's, instead of replacing them in 1000rds (=/-200rds). Of course, I'm shooting them a bit less, too, since I'm no longer working our old LE range and shooting a few times per month.
This reminds me of when I learned one of our guys who owned a CS45, which he used as an off-duty weapon, hadn't replaced his mag or recoil springs since he'd bought the gun ... 10 years ago. Granted, he only shot the gun a couple times a year, but that was kinda outside the then-new mag/recoil spring replacement recommendation S&W was telling its armorers, of every 5 years (left fully loaded) or 5,000 rounds fired.
Prior to that, the company basically just told us to monitor functioning, checking for positive slide stop/slide engagement during live-fire on the firing line, and also at the bench when inspecting empty guns/mags at the bench. This was done by manually racking the slides as fast as possible to see if the mag spring lifted the follower quickly enough to lift the slide stop into the slide's stop notch. We were also told to compare free length of used springs to new springs, and given a broad rule-of-thumb for serviceable free length of working recoil and mag springs.
Anyhow, while this guy with the CS45 wasn't experiencing any feeding or functioning issues with his 10 year old gun and springs, using the various 230gr factory ammo we provided at the range, I recommended he order some new springs. Just to err on the conservative side of owner maintenance practices to help keep his gun running.
My CS45 guide rod & plunger (left) and a TSW guide rod assembly (right). That's the polymer rod plunger I've been running for quite a few years (and many cases of ammo), minus any plastic fuzz I've removed.
More comparison pics of steel and plastic plungers for guide rods.
Now, installing the slide stop lever's pin in the frame is something that ought not be done with excessive force, of course. Unlike the guy in the video, I usually finish putting the slide/barrel on the frame, and then retract the slide until the slide stop notches in the slide and frame align ... and then I either tip the muzzle
up, or use the tip of my finger to
push the barrel to the rear ... so the barrel lug moves to the rear and clears the frame hole where the slide stop pin is going to be inserted. Tipping the barrel up lets gravity do the work for you. (Grasping the frame so your thumb and web of your hand is under the grip tang of the frame, and your fingers are up and around in front of the rear sight base, let's you squeeze and hold the slide and frame aligned to let the barrel tip and fall back, or you can hold the gun horizontal and push the barrel back, depending on your preference.)
Don't mangle the plastic plunger by trying to push it
through the steel barrel lug that's in the way of the pin you're trying to push into the frame hole. Won't work.
Just some thoughts.