Some, but not all of those proper oddballs. I don't want that white plastic thing and wouldn't admit to it if I did have that one. Yuk! I do have an oddball clear plastic one which has a Z on the end the cap thread - I've never seen another thread with a letter on it. There's that No.37? too, that German twin slot thingy from the '50s.
Yeah, some proper one-offs ... or "a thing" once two or more turn up.
Talking of wartime, I have one with what I thought was a unique handle, perhaps personally customised, and left it with that thought. Until another turned up and I spotted yet another on eBay not so long back. I have another with a more bulbous bakelite handle than usual - definitely Gillette as it has the logo on the end.
Never say never ...
From collecting 1912s, you think you know 'em all ... and then an oddball comes along, which you discount as it doesn't fit into the schema that you've built up in your mind. Then another of the same comes along and then you see them everywhere! And then you start again ...