Hi, I have a cal 30T in a case whose internal back number is 10422722. As most of you will no doubt already know, this suggests that the case/watch originates in the 1940s. It's been fitted with a modern plastic generic glass and I'd like to replace it with a genuine Omega one, but have no idea what case style number this represents - or if, in fact, a genuine Omega crystal is even available for it. Any wisdom to share out there? Thanks in advance!