identifying model

Hi all. How does one determine what year/model? I’ve a Polaris ATV – Pretty sure it’s a ’90s model. It’s a 350 2-stroke, 4×4 liquid cooled. Stickers say 350 Liquid 4X4. Can’t find any model/year stamp anywhere else. I bought a property (estate sale) and everything with it, including the Polaris. The thing quit on me the other day – lost power, then stopped. No compression. Pulled the top end off, and there we have it, piston is toast. Previous owner had disconnected the oil injector line (either because it didn’t work or he didn’t trust it) and I’ve been unknowingly diluting the pre-mix in the tank by putting in straight gas. Big end moves freely with no binding or excess play. Haven’t run the machine hard, just riding around the property at low speeds.
Looks like a fresh top end will be less than $150, I’m willing to gamble on the bottom end being ok and rebuild just the top. So, I need to know how to determine what model and year this is to order parts. Any suggestions? My guess from comparing pics is it’s a Trailboss 350L, but that is just a guess and no idea of the year
-Matt