Where would my VIN be?

I've got this Fimco 505 - T and I remember seeing in the advertisement for it that it could be registered, so I'm wondering where I would find the Vin stamped. Also. could I register it as a moped? I know that in Michigan the law is 50CC but it used to be a 100 CC maximum so it changes as engines get more efficient , so I figure a 5 horse tecumseh from back then is only a 170 or CC, so would it be exempt because of the laws back then? ( Assuming there wasn't a limit.)