Keep in mind some bikes were titled by the engine number and some by the frame number. Have both ready.
My understanding is it is different by state. I hear Michigan uses engine numbers sometimes.
Most have no mention of engine number, and with these Hondas it's mostly vin vs engine# is unrelated to perhaps err by 100 bikes or more.
A motor swap might be obvious, by manufacture date, etc. Or maybe if it was stolen, but probably not I'd think.
As well, it might be a number to use to get any sort of title to it should all else fail.