The reproduction panels are nothing like the originals.
The originals are pot metal and smooth cast (no grain whatsoever). Also each rib is a double rib. The four mounting studs that are towards the center are studs casted as part of the panel, used a rectangular rubber wedge, and a stamped quick nut with a wide flange built in.
The reproductions are aluminum and rough cast (look like sand casted). The ribs are single. The four mounting studs have threaded inserts, use an round aluminum wedge, and a captured washer nut.
As Jeff was inquiring, if your door tag paint code is a 2 digit code, then the panel (and other rear parts) were painted a metallic gray.
Do as Charles suggests, find good used ones!
Regards,