Info wanted on old Diebold safe

I've got an old Diebold safe that I'm trying to find out it's approximate year of construction. My best guess is post WWII but before 1958. However that's based only on my rough knowledge of wrinkle type paint finishes. I've been unable to identify a model number on any of the applied aluminum plates. (Links to pics deleted. Please email for links.) Also, there's a (roughly) 3/8" dia. hole in the bottom of the safe that I'm trying to figure out. At first I thought someone had drilled into it to open it but the filler material visible through the hole shows overspray from painting. Also, the hole edges look too clean and the filler material looks as if it were cast, not drilled. Surely it wasn't it normal for a small Diebold safe to have a hole in the bottom? TIA, Ray PS: I forgot the obligatory "I do have the combination".