Got it...I have never seen that mark on any Oberndorf issued K98k receiver...especially on the rail.
If the receiver had been out of spec, it would have an additional E/135 acceptance or an "asterisk" stamp.
The only "star" style stamps were used on Chilean contract 1935 carbines.
Refer to Volume I, page 256 on the lower left image of the cocking piece on the S/42 1937 image gallery.
That cocking piece was from a contract run (leftover) and was diverted into military production.
This receiver could have been left over but its only conjecture on my part.
As Jon Speed mentioned in one of our conversations, Mauser never wasted any components and would
use as much inventory as possible, especially during critical delivery periods.
Case in point were the late diverted Banner receivers used in military production in late 1941.
What is the letter block of the rifle?
