Yup, noticed this too. They used to be 1GP... and infact the metal plates still do. It's the golden looking ones that are worth much (even if both are called plates). Including the ones at the End of Time, which are *supposed* to be worthless, but worth 9000 (about 4500 really from vendors depending on bartering, rep, attitude) if you pick all up.
Quite the change from beta, eh?