Not passing smog is a big deal especially for a new buyer. afaik, by law, its seller's responsibility to make sure it will pass smog. You & the buyer need to take it to a smog station to pre-test the car to make sure it will pass before you give you money away and not legally own the vehicle.
If it will pass, lucky you. if it won't pass, there can be a multiple of causes and if you are new to this, you most likely will get the run around trying to make it pass and throwing your $$$$$ away and cry on Prime. It happens more than you know.
fyi, Ramon of Niguel Motors in Laguna Niguel is a great,reliable, honest source to help the dialogistic and he uses Duke of OC smog in Dana Point. BAR keeps lowing the smog number for the early cars like yours so its quite tough to pass. I have a 93 and after it failed the last smog, the BAR numbers got lowered automatically for the re-test, lucky I installed used oem cats and that was the problem for me.