From what Nick posted it sounds like it all comes down to what the DMV classified it as, A, B or C. If it really does 45-50mph and got classified as a class B or C, the classes not requiring a motorcycle license, someone at the DMV wasn’t looking at the paperwork very closely.
It’s even possible it’s not classified as a limited use motorcycle at all since 45-50 is over the speeds allowed for even a class A moped, which list a top speed of 40.
DMV is your best bet. Might need a VIN to get a definative answer.