Many parts for the '94 will interchange with 1900 parts. In the case of the trigger guard, there are two types - one screw and two screw versions attaching the guard tang to the stock. The difference between the '94 and 1900 guards is that the s/n was engraved on the '94 tang being while stamped on the 1900.
I have a '89 guard on eBay right now -- don't know if it can be fitted to a '94.