they weren't a issued nazi item [unless a Generals 1st type ]... Don't think there is no way of telling...

Maybe try very lightly to see if anything unscrews,,,then you could check threads to see if they are metric.. Still wouldn't give you age though,,, just not from US.
: Warning,,you could damage it by unscrewing it:

It's nice looking and if doesn't cost a fortune why not keep it..