Frame is an October 1990 so yes made for the 1991 model year. The forks seem rare by themselves and overpriced which is why I was happy to get the frame with them, people seem to ignore complete frame sets.
Those 1" Pepperoni forks are quite rare for some reasons : Only the SM2000 and Omega used them in 1990, and the SM2000, SM1000 SM800 and Omega in 1991.
More rare are the 1" Pepperoni forks made for the SE (Rear suspension bikes), because they got a specific hanger for the Force 40 pulley