Sounds like an Argentine Mauser. With the crest scrubbed in VG condition they are worth around $400, give or take 50 for the long rifle. I have no idea what the cavalry carbine is worth. With the crest intact they are worth around $150 more.
Here they are.
__________________
"It is a just person who disobeys an unjust law."
Plato (427-347 BC)
Like Hounddawg said it is an Argentine. Argentina had a contract with Germany and they received quite a few of these rifles.
Depending on what the offer is and if the rifle is in it's original configuration then yeah its a good deal. I actually traded my Chinese Paratrooper for an all numbers matching Very good+ m1891 Argentine straight up, I came out on the better end of the stick IMO. These are probably one of the best finished mausers out there, it's hard to find one that was made cleaner and tighter.
But you gotta make sure you shoot lighter loads as much of the surplus/commercial ammo available was made for the Argentine that uses the M98 action. These m1891 rifles were among the first smokeless rifles so they are not the strongest out there since no one really had smokeless powder figured out completely yet.
This is why the Argies are well worth it. Although this is only 55 yards, I'm at the point that any further away it's just an orange blur. Right now I can still see a small orange blur inside a larger blur to shoot at. The printing high is to be expected, as the minimum setting on the sight 300 meter.
__________________
"It is a just person who disobeys an unjust law."
Plato (427-347 BC)
I recalled something my uncle told me in the '70s about the old target practice, and I applied it when shooting with my room-mate's Yugo. You have to aim low, not the modern "Center of Mass". Have the target "sit" on the front sight and you'll hit the X ring.
My buddy shot his clip, then his buddy from Germany shot; Misses. I was last and had the coke bottle "sit" on the front sight and a solid hit. He wasn't all that happy that I got a hit, but...
Good luck.