I've been doing quite a bit of research as I inherited one last week, awaiting delivery via canada post.
I know the 1871 had a rifle, a jäger and a carbine. It seems mine will be a carbine. I have also read about the 71/84 and Serbia ordered 5000 carbines from Mauser in 1885. (Guns &Ammo, surplus firearms magazine, 2011, pg 43). Caliber, I can only assume, was 11mm as well.
The 1871s are all single shots and the 71/84s had an 8 round tube mag, originally. Lots of the mags were cut down when the rifles were sporterized.
I don't know total production numbers for 71/84s, but I have seen figures of over 1 000 000. Only 5000 of those are Serbian contract carbines. If yours is in fact one of these carbines, it is a rare bird, indeed.
Seems like you need to do some more intensive research...