Hello Bill,
I do have an authentic, matching 1918 DWM artillery (# 5567 b)that has some even patina under all of its blue that does have some deep circular machining marks quite visible on both flat sections of the "ears" on the frame.
Maybe this happened at DWM during the last days of WWI orders...
If you send me a Private Message with your e-mail, I would be happy to send you some high resolution jpegs of these areas on my arty...
Regrads,
Pete... <img src="graemlins/yltype.gif" border="0" alt="[typing]" />