I may be way off but 12th artillery field battalion weapon (waffe) 2.
Forumite Germania would probably know better and can be found sometimes in the Bernard Levine ID section. Others in there probably know as well.
The Antique&Military section at swordforum.com might get response by Dale Martin and/or George Wheeler. If you are German literate, the deutsches-blankwaffenforum.de forum would surely nail it down.
Although a quite early pattern, there are a series of model years for them and somewhere I have seen picture files for carry of these as late as WWI.
The numbers bring up the sale and pictures. It looks like you did ok, all in all.
Cheers
GC