Kevin:
I'm looking at the page in Pate's book you're referencing, and I admit that my statement as I worded it is too absolute.
However, I think Pate's wording makes it clear that the gun we dealt with here does not fall under the exception. You will notice Pate stating that this pertains to those guns NOT purchased by DSC directly from the manufacturer, but purchased "by the Army for the DSC" and "ultimately charged to the government contract"; those were the mostly unmarked guns which had to be returned to the Army, and which the Army apparently then didn't know what to do with.
Mike's letter from Roy makes clear, however, that the guns for Bethlehem were part of the direct DSC contract, not the Army contract, so this gun would not have been affected.
In regards to the letter you posted, there is no doubt at all that you are correct, but there is no evidence that this transaction is in any way related to the DSC. In October 1941, the US wasn't even at war yet. That may just have been a local Baltimore arrangement.
Did you notice the other thread on the possible USMC Victory? I may have to modify my statement of doubt about the authenticity of the USMC stamping also. It'll be interesting to see a photo to compare to Mike's marking.