m66 frame mark question

[Gress]

What is this mark?

Thanks.

 

[VM]

IMO, some sort of Inspector's or Assembly stamp

 

[jughed440]

sorry to be a thread stealer...but i would like to know what this sticker with "37" on it indicates.
also, every 66 i've owned except this one has had "S" (stainless) stamped on the frame. is the lack of an "S" common? and what does the "Y" indicate?

once again...sorry to steal the thread

 

[Gress]

IMO, some sort of Inspector's or Assembly stamp

Thank you.
Inspector's would be a sticker, not a stamp...this is what perhaps jughed440 one is. Assembly stamp it is, but I was hoping to learn what are these numbers meanings.

No "S" or "Y" on mine..