I own an Argentine Mauser from 1891.
Other than the ground off crest, it's probably had 50 or fewer rounds thru it.
Also have an Argentine Mauser, an 1898 carbine. It's got the crest and all the markings -- the stock has an arsenal repair and the sling studs were clearly converted from artillery to cavalry, but other than that it looks almost brand new. As I understand, the Argies at the time were "modernizing" by exterminating river pirates, banditos, and the occasional Indian tribe. For the kind of stuff they were doing cavalry was much more useful than artillery and many of the artillery carbines were converted to cavalry configuration (different sling setup for horseback).
Many of the Argentine Mausers with ground-off crests were sent as material aid to various rebel groups in neighboring countries, who the Argentines didn't want to be directly linked to supporting, hence the removal of the crest.