Boat Not in NADA guide

[Tmacmi]

I have agreed to purchase a Spirit 28. I have sufficient cash, but I'm thinking of financing it since my rate would be low.

There is no Marine Survey needed however they want proof of value. They said they typically just use NADA guides. I look in NADA and the only entries for Glastron/Spirit are for a 23 foot boat.

Any reasons why its not in NADA other than its relatively uncommon?

Any other ideas of how to show value?