I just replaced the wiper arm and blade on my 1990 16' Angler this weekend. Took the old one into the shop with me and the only match I found (but a perfect match) was Sea Dog Line part #'s 410054-1 (arm) and 411154-1 (blade).
Now, I have no idea if this electric wiper was factory installed or if it was an aftermarket addition by the original owner. It appears to be the cheapest model available, which leads me to believe the previous owner installed it, based on all the other "accessories" he had on the boat when I got it. Replaced the arm because the tension spring loosened over time and it was flopping around in the wind as I drove down the highway.