Mikey's coin is definitely double struck. Most Greek silver needed more tthan one blow of the hammer to transfer the design and a little shift of the die would make this much of a double. Such things show worse on high relief coins.
My Thasos examples. I don't have a Skepsis example. 16.8 gm 30.2 mm 16.6 gm 30.1 mm 16.7 gm 30.2 mm Doug, in my Thasos post a while back you said you wanted to do a little more research before purchasing a coin from the series. Were you able to research a little more or did you find a deal you didn't want to pass up? Nice addition.
I decided that this one was normal enough that it was official. So many of them are obviously barbarous and many of the barbarous ones have been listed as modern fakes in some places. I do not seem myself buying more. I have had the one below for a long time. What is the difference between my new and old and your three? I consider all believable as far as being ancient. Were all from the same mint and general time? I do not know.
THRACE, Thasos AR Tetradrachm (After 146 BC) 16.72 grams, 31 mm Obv: Wreathed head of Dionysos right. Hair is neatly braided, vine-ed & berried with a few locks of loose hair cascading down to the shoulder Rev: Hercules standing left, holding club & lion's skin with control monogram. HPAKΛEOYΣ ΣΩTHPOΣ / ΘAΣIΩN. Grade: gVF to aEF Other: SNG Cop 1046ff. May 2014 Pecunem Sale 16, lot # 86. This statue of Dionysos is kept at The Louvre: This handsome fellow is the god of the grape harvest, winemaking, ritual madness, and ecstasy in Greek mythology. Apparently, there was Wine, Merry Making, Theater, and Ecstasy available in Thasos.
It looks like the thunderbolt(s) that Ancientnoob has shown me on several of his coins of the ancient World. As I recall, we were wearing beer glasses one night trying to figure-out which coin first depicted a thunderbolt device.