Serial number is usually on bottom bracket.

It is not "basically" a moped, it is not a moped at all. You cannot ride a moped by pedaling (ok technically you can but have you tried).

It is a motor assisted bicycle (or pedal assisted motorized bicycle) and that's how you want to approach this. The key info here is that it doesn't work w/o the pedals i.e. you help the motor and it helps you. You don't padal assist a moped or scooter and that is what sets these apart. DMV/DOT's typically do not know what they are talking about and just want to generate revenue i.e. take your $.

Call your State Patrol, Vehicle Inspection if you have one, and ask about motor assisted bicycles under 50cc.

When you ask about moped laws you get moped law answers not motorized bicycle law answers.

It may end up that they classify them the same but most don't.