I wouldn't worry too much about specific years and problems. I would look for the unit that you want in the condition that is acceptable to you. We had made the decision that we wanted an AS but the new ones were out of price range. We felt we wanted something in the 22-27 ft range,
Those are the hardest ones to find. I knew I wanted something between 1969 and 1985, I just like those the best. We ended up with a 1975 31' Sovereign
. Not exactly the 25 footer we were looking for
But this unit was in a condition that was acceptable to us, the price was what we were willing to pay. A very large factor in the condition of the unit will be the Previous Owner(s) and how well they took care of the unit. This will drive the price too. I have seen gently used, well cared for units from the late 60's that looked fantastic, as well as some units fromt he early 90's that looked like garbage because the PO's had never done anything to take care of them. FWIW Clear coat can be redone if necessary.