If I'm understanding the cover_art_archive schema correctly:
INSERT INTO cover_art_archive.art_type (name) VALUES ('Tray');
Someone with production database access?
That bit is easy, it is, as always a problem of coordinating caches.
But once that is done, the caches will all be cleared at some point anyway, won't they? (at most next release I guess?). So this is the only part that really needs to be done... or you mean you're worried you'll be seeing it on one of the servers but not on others and everyone will get confused?