Well, I tried to take some decent pictures of the "extra" artillery barrel's markings, however I had a tough time getting clear/crisp pictures of the markings.
Below is what I found. It's a pretty decent picture of the multiple markings on the bottom of the receiver. I tried to get decent pictures of the side of the barrel but they didn't turn out very well.
There is a crown over what look like the letters "RG", then under that marking looks like crown over something, but for the life of me, can't figure out what.
The right side of the receiver looks like crown over a bomb and to the right of that mark, is the German Waffle mark over three letters, but I can't make out what letters.
Any input is greatly appreciated!!