I suppose call them and ask them to look at the headstamps of their b20b's, they should tell you things like p75 or p75-2, p75-(x) where x is any number, and then p8r. I believe there to be another head stamp possibility pr
-4 but that is the same thing as the p75 just from an earlier year. Also make sure it does not have a knock sensor if you want the p8r.
Or look in the honda marketplace on this forum, maybe someone has a p8r head lying around and you could just put that on the b20 you end up getting if you cant find one with a p8r head.