It's not a rookie card. His rookies were in the 1990 sets from Score, Topps, Fleer, Pro Set and Action Packed.
There are two different '91 Stadium Club Smith cards, the card from the regular set and the one from the Members Only set. Both go for a couple of dollars in raw form, more in graded card holders with grades of 9 or 10. But the cost of grading makes it not worth it unless you know you'll get a 10.