Yes, I just removed the barrel from the stock on mine and it has the exact same proof marks as yours, but date code of AM for 1984 so one year before yours, and exact same rear sight, serial number 6921.
Did you get a nose cap and wedge escutcheons with it? If so are they iron or silver? If silver my money is on a Western Arms or Allen F.A. kit from 1985-ish.
Here is a pretty well documented run down on the history of the Uberti/Ithaca/Santa Fe/Jedediah Smith/Western Arms/Allen F.A. Hawkens.
http://grrw.org/uberti-santa-fe-hawken/