Well i'll be the son of a monkey, i have a Luger screwdriver just like that except it was made in Switzerland in the 1870's when good old George was a young man and way before he thought of refining the Borchardt.
It is a standard issue Swiss screwdriver for the Vetterli rifle and as i said issued 1871. Note the Bern trademark (cross in shield proof as they call it)!
http://theswissriflesdotcommessagebo...rs-Guisan-Help