OK, I hadn't looked at them that closely. The early Kato "Smoothside" coaches are UP prototype, as far as I know, and I have a couple for my 1974 Amtrak trains. If one wants UP coaches, finding those would probably be the best bet.
NO, I don't have any extras. My extras were all repainted GN Big Sky Blue, as the GN bought some just before the BN merger.