For what it's worth
I was very involved in Smith & Wessons from the mid 70's through the 80's and here is what I remember.
I never saw a 50's, 60's, or early 70's piece with any problem in the way they looked or acted. In the 78 and later pieces, there were problems, mostly in looks, some in actions.
One day, while I was talking to someone at the factory, and I do believe it was Roy Jinks as a matter of fact, we were discussing some quality issue and as a part of that conversation, he said that production had increased some outrageous percentage and then some outrageous percentage more and THAT was why we were seeing quality issues and mismarked model numbers etc., etc.. Now, in that period, I saw some of the best work ever, but I also saw a lot that was less than I was willing to accept. We were able to straighten a lot of the stuff out, but we also had to lower our standards as to what was acceptable. The factory was very gracious as to taking care of any problems, even though it could take a while.
For what it's worth.