1920 DWM question

[saxman]

It seems to me that only a government rebuild would assemble a cannon and frame with the same number but different suffixes, remove the unit marking, put on a new sideplate with the two digits on the bottom and rust-blue. Plus, everything fits and works together perfectly. By the time I got it, though, that sideplate was a wreck. Somebody had tried to remove pitting with some kind of end mill, then hot-blued it. I eventually found a beautiful commercial plate with the exact finish and wear, but a different number (on the bottom).