The state probably issued that # as I seriously doubt that hull is home made. 2 scenarios I can think of...
1) The hull was made prior to 1972 when HINs became mandatory. The state may have retro-issued a HIN for registration and tracking purposes.
2) It was stolen at some point, original HIN removed and it was re-registered as "Home Made". Boat registrations aren't typically as well regulated as automotive and thieves know the loopholes. Hope that's not the case here as that hull looks bitchin as hell.