Real P hinges probably carry real P prices- we're cheap a**ed replica owners, cast aluminum hinges are what most of our cars already came with and they work. Also, with the firewall not being in exactly the same place I don't know if original hinges would work (although I suspect they might, but it all seems like too much work to me). I do like the idea of them having the latching mechanism though.
And to be honest, I don't know if I could drill enough holes in them to quell the.... uhhh...urge... 