Yes, the last 2 digits are the year on a pwc. I also was looking up ski-doo vin numbers and this is not from a snowmobile. Their vins are either 9 digits for older models or 17 for newer ones.
So considering the age of the ski, if it was stolen, I doubt anybody is still looking for it and insurance claims have long been settled.
FYI there should be a secondary HIN number inside the hull somewhere. On my 1992 XP it in the front next to the gas tank. I am not sure what you are buying but it looks like an HX. I have seen some people say it is under the oil tank on that model.