That H&R was certainly not made in 1950, more like 1900. Whether it was made in the black powder era, I don't know, but there is a connection between shooting .32 Longs in it and the fact that it is now loose.
If it functions OK and you want to fire it now and then, it will probably work OK, but having worked on dozens of those old guns I would not trust any of them for serious use. They sold for under $5 (your gunsmith was right about that) and were never intended to stand up to a lot of use. Their old springs break without warning, they go out of time easily, and they are simply old. IMHO, it is time to give that old timer an honorable retirement and find a good used more modern gun for the glove box.
As for selling it, I am afraid you might not get much; they usually sell for under $100 and many gun shops won't touch them because they can't warrant them on a resale.