You're right. This is very clearly a sign of substandard workmanship. I'll be very happy to PM you later with my FFL details to take that hunk of junk off your hands.
^^^ Take him up on this offer and be done with it.
I agree with the comments about defending this QC, as it does nothing to help correct it.
The finish issue is not QC related, but they need to make a MUCH better effort to warn consumers about using certain products on the newer finishes because like mentioned Hoppes 9 has been a staple product for decades. Most people are well versed in the use of a revolver, so who is gonna read the manual to page 32 to discover a rather VAGUE statement on solvent use?
As for the rest of the issues, they are definitely QC related. Why is it that everybody for the first 75% of the thread just bashed him about screws coming loose and not the B/C gap, end-shake, canted barrel, or stop pin in rebound slide?
First, I honestly have never had a screw work loose, except on my Colt SAA, which is understandable due to the design. My 2 S&Ws have never had the screws loosen, but they aren't new productions. However, I do dis-assemble every "new to me" gun I get and then tighten the screws myself upon re-assemble without the use of polish or loctite. They stay put.
The rest of the issues, you can say they are all "within spec according to S&W" but that is another excuse. I would never own a gun with the specs the OP has stated. I am used to B/C gap of about .004 and endshake of .000.
However, this could all have been solved by thoroughly inspecting the guns before purchase, except the finish of course. Which makes me ask the question, why would they make something that can't use a staple solvent of the last century?