Part lists / spec lists

Hi there! Is there a database online somewhere that contains part numbers and specs for things like crystals, gaskets etc? I just picked up this beauty the other day, and after I cleaned it I noticed a little fogging on the crystal, so it's time to replace the caseback gasket I think. I'm having a tough time finding any place that lists the size and thickness though.

The crystal is a bit scratched, and if I can't polish it up, I'd like to replace it, but again I'm having a tough time finding the correct part.