RB24 One Cent Green Proprietary pair with
prominent screw head impression in upper right.
Close up of screw head.
This image was sent to me yesterday by David Thompson of Nevada, a collector of battleship revenues and a fan of this site. David traded a couple of old Roman coins for this piece when he was in England many years ago.
The impression of the screw head is an image of the screw used to hold the plate to the bed of the press. I have seen many of these types of margin screws but this is the clearest yet. Thanks Dave!