Watch List notes:

KINGS of MACEDON. Antigonos I Monophthalmos. As Strategos of Asia, 320-306/5 BC. AR Tetradrachm (16.5mm, 4.29 g, 12h). In the name and types of Alexander III. Sardes mint. Struck circa 318-315 BC. Head of Herakles right, wearing lion skin / Zeus Aëtophoros seated left; [Γ(?) in left field], A below throne, amphora to outer right. Price 2651; cf. ADM I Series XVIII. Lightly toned, off center on reverse. Good VF. Extremely rare, only one in Pella, none in CoinArchives, none in ADM.

The left field control mark noted in Price is uncertain, as the drachm he illustrates (also the example in Pella) is off center.