A way to identify M1921 buttstock oilers?

[reconbob]

       I am not a Colt expert. But Doug Richardson was. I was going thru some

of his stuff and found a zip lock bag marked "Colt" with a nickel plated buttstock

oiler inside. He also had another bag with nickel plated G.I. oilers that are 

marked "NOERA Mfg Co." I put them side by side and there is a noticeable difference

in the radius or rounding of the corners between the two. The G.I. corners are more

square, the M1921 corners more round. The photo says it all. So is this a distinctive

characteristic of M1921 oilers? Or just a random thing?

Bob

[Autorotate]

The threaded “neck” of the oiler appears a bit taller too or is that just how you took the photo?  Trying to gain knowledge on this subject.

 

Thanks!