Ok, here is what I remember. The prindle 19 came out in 1985. In 1987, the factor added a bulkhead in front of the front crossbar or at the front crossbar. I don't know why. In 1992 the rudders were changed (more elliptical). The square top was later added. Probably around 1997 from the factory. Any year will work just fine for racing. Add the square top and upgrade the rudders or add a spinnaker will make the boat even be faster.
Jonathan Grant
Mesa, AZ