I think I read somewhere if you have the Cent you can ask for a Plat that is basically the Cent but just not black (same number, same benefits, etc). This was back when the Plat was plastic so it was easier to use at gas station/grocery stores, and it won't draw attention. I guess Buffet probably could request a green card as his Cent and they would gladly comply.
Why would Buffet want a Centurion?