I have an Argentine Mauser from 1880.
It's in 95 percent condition with matching numbers on all the parts.
I'm guessing it was a parade weapon based on the condition.
You may not have what you think you do.
The 1891 Mauser was Argentine, but in 1880, the only possible Mauser rifle was the 1871 model. There were a few of these that made it to Arentina, but they were primarily used by the provice of Buenos Aires fighting in a civil war.
If you have an early Mauser in beautiful condition, I am guessing its an 1891 model (same as 1889 Belgian, and 1890 Turk). If it is not an 1891 and you need help identifying it, I’d love to see some photos.