HELP! 1918 DWM Artillery w/o Acceptance Marks

[Helio-Abt]

Sorry Jerry,

I wanted to add this to my previous post but posted it as a new thread. My fault!
The original states:

I am looking at a possibly re-blued, all-matching (incl. magazine) 1918 DWM Artillery for possible purchase.

The odd thing is that it has no acceptance marks on the right side. Parts are all marked , barrel is proofed with an '8.82' and serial number.

The picture shows a 1938 with marks where the one I am looking at has none.

It does not appear anything was ground off....

Thoughts?