I did my homework when I won the auction, downloaded an owner's manual online (thanks Brian) and bought a repair manual. I checked the jets because there is just a little over 700 miles on each, and, sure enough, they still had the break-in jets (58's). I've already installed the 56's and the top speed is the same, but I get less "four cycling". Mine is definitely a 30MPH; it's labeled on the frame and the carb confirms it.
Thanks much for the info on the belt. It will save me a lot of time and aggrevation, not to mention the money.