Because when AA first had the A300 they were paint grey.
Photo © Joe Pries - ATR Team
Photo © Artie Caissie
I thought Airbus's could not have bare metal liveries, that is why they are painted in a primer before painting at TLS or XFW.
Photo © T.Laurent
But how come the A300 when at Airbus is not totally in primer.
Photo © French Frogs AirSlides
Also why is the section under the tail composite (I think), as well as just above the cockpit.
Photo © Rudy Chiarello
Photo © Joerg A. Dittmer