There was a brief discontinued period for the SAA after 1982, but then were resumed right after that. There was no changes made to the revolver in this time, so all revolvers made since are still 3rd generation. Many references were made to it being the 4th generation, but I believe Colt will tell you there is no difference, and they are still 3rd generation.
As to quality, the early 3rd generations were a hit and miss. I have one .44 special that is a user, and the fit is not the best. I have another identical .44 that is one well put together gun. It has magnificent case colors, and looks great. However, the cylinder throats are a bit large at .432 average. The barrel is .4275".
I just bought a 1997 vintage nickled .44-40 that is both put together wonderfully, and has tight .428" cylinder throats and a .427" barrel that is a great shooter. It is the best shooting as well as the best fit SAA I own.