Vintage bezel expert oppinions

[007Sub]

Hey all, I have two 5513 subs one from the 70s and a friend's from the 60s with me right now. I'm noticing that there is some very slight variation between the bezels which I have been told are both period correct. Now, I thought that they should be exactly the same... yet they do look slightly different. Check these photos out and let me know what you think. Are they actually different from 60s to 70s? Is this just a product of wear? They are in both decently crisp shape considering their ages... I'd appreciate your insight here on this!

Thanks all!
Greg

p.s. There are 2 photos of each variant... lets call Variant A. the top one, and variant B. the bottom version of each different photo... i hope this makes sense