As others have said, if it is an original Winchester 1892 from 1892, it will have these markings:
* Tang roll-marked Winchester Model 1892- Trademark
* Barrel roll-marked Manufactured by the Winchester Repeating Arms Company, addresses and patent dates
* Barrel roll-marked with chambering information directly on top of the chamber (guns produced after 1921 had chambering info on the side of the chamber area of the barrel).
The barrels were not proofmarked prior to 1898.
Also, if it is an original Winchester product, the rifle will have the following features:
* Hammer will have a roll-marked, bordered checkerd area on the top of the hammer ear.
* The cartridge carrier will be machined steel.
* The barrel bands are slightly rounded in cross-section, with fine threads.
* The front sight blade is pinned between two "ears" and is integral to the barrel itself.
* The rifle mainspring is a flat spring, not coil.
* If the rifle has a saddle ring loop, the loop is welded.
FWIW, replicas of the Winchester 1892 rifles have been imported from South America for several decades.