Savage Model 99,“0” mark.

[2dasea]

I have a 1956 Model 99 in .308. On the left side of the action directly below where it is marked Savage Model 99 there is an oval or “0” mark. I have always wondered what this signifies and haven’t found anything on the web about it Anyone know?

[Mad Dog]

Either an assembly mark or a date code mark which was struck to lightly to leave the date code inside it but usually the date code on 99's is on the lever boss so I'd figure more an assembly mark than anything.