johnsonlmg is correct. once the sharp edges of a chipped bolt are removed by honing, they work fine. I get it that most people would prefer a NOS bolt, but they are becoming more and more scarce and expensive. A properly polished bolt will function the same.
I agree with Bwana, the M11/9 would be a great choice pricewise. The Lage slow fire upper turns it into a very shootable subgun. Also suggest the upper that accepts the drums instead of stick mags, 70+ round mag dumps are a thrill.
My thanks to all that responded with great practical advice. The consensus seems to be if it's not broke don't fix it. My MCR and M60 run just fine, so no lube for me.
The observation that the Uzi was in all probability test fired after manufacture sounds logical. If the gun is then "test fired", I would think it is no longer new in box. I don't see the value in additional firing.
I totally agree with skipping the West Hurley. The 1928 WW2 will accept both sticks & drums and has some history. The 21 is a good choice, but expensive and less likely to want to shoot.