How to tell if a t19 is legit?

[330ci]

So I bought some old watchmakers stuff and found a few Rolex parts in here. An insert that’s fairly mangled and a crystal that was marked 5513 orig on the container but it wasn’t the Rolex container, just a plain envelope. The insert was in a 5513 Rolex package from I assume the replacement. I want to make sure what it is before I get rid of it. The guy stopped watchmaking in 1990, not sure if there were any fakes around then or not. And the part was likely older than that.

Any info about either would be appreciated