Who knows? Those guys had a lot of idle time especially during winter months and a lot of them came up with different ways to combat boredom. I've seen some really artful carvings and such so who's to say the owner didn't personalize it. Just one of those things you'll probably never know. If the gun was used by an infrantryman it was most likely shipped home after a few weeks of carrying it around. Most pistols issued to infantry were either shipped home or discarded by the roadside. A cavalryman might personalize a favored pistol because they were usually fired till empty and discarded to be retrieved later if possible.