Their pretty easy to rebuild, I did my first one when I was around 8 years old with no manual or instructions. Just pay attention to the order you disassemble it & you’ll be fine. Parts are readily available also.
When real items are unobtainable folks will pay top dollar for reproductions. I made around 200 of these reproduction AR-15 carbine stocks & sold every one a few years back. They were only a few made originally before Colt developed an easier cheaper design...
It’s getting too hot to do much bicycle work here in Phoenix, but I have a replacement frame thanks to Danny the Schwinn freak. The letter on the serial number is worn off, so the exact year can’t be determined.
I like this fact.