basically nearly all 28x and 38x are idistinguishable
(apart from very minor things like decals, sometimes wheels.. with or w/o brush guard etc...)
and the engine is.. well replaceable anyways
So in short: look at the manuals I linked and see what you feel more comfortable with.
The cart has been used at a carting track, then when it broke my father in-law bought it cheap. He then fixed it up 10 years ago, then the chain broke and it was left outside for about 8 years...
As far as I know the engine is original to this cart.