I'm not so sure it was German Military issue only, unless of course it was a special order, one never knows.
It looks like a pretty bog standard R75/5 and going by the indicators, its a short wheelbase model (SWB), which would put it between September 1969 and September 1972. If it only has provision for one mirror (left side) then it is pre 1971 as BMW never made a motorcycle with two mirrors until 1971.
I had two /5 BMW bikes an R75/5 and an R60/5 both SWB.
Overall I've done about 1.3 million kilometres on BMW bikes, don't even ask about the other million or so on other makes of bikes.