Mid 19th century original 5 string?
 

Chewing the fat with a retired symphony player the other day, he told me about a section mate that played a mid-19th century (he thought 1840-50) 7/8 original 5 string, probably German or Tyrolean. Were 5 string instruments really made around this time? I can only imagine what the gut B string would look like!

They had covered wire/wound Guts way back from the late 18th century from what I have read. I don't know if they were in use all across Europe but I did read of its invention from that far back.

V-Bass
 

There were a lot of 5 string basses in Vienna/Prague (anywhere the Hapsburg culture went) back in the 18th century. The bottom two strings were generally wrapped gut and the top three raw gut.

old 5s
 

I just saw an old 5er made by Benedikt Lang I, who worked in the Schonbach area c.1920. This is not B.Lang II from Mittenwald but might be related. It looks typical turn of the century German/Czech and was made originally as a 5-string. Not quite 1840-50 but old enough to be settled by now.

Another thing to note about older german 5 string basses is that many of them in the area of Vienna would have been used in viennese tuning (FADF#A). Whether the bass your friend has such as bass, who knows, but it's certainly food for thought.

more about viennese basses and the tuning here.

Cheers,

Alex