Thanks all.
@tdziemia, that's exactly right. I suppose this was an attempt to flip the coin, but exactly how a $300 coin was consigned and ended up in an unattributed job lot is beyond my comprehension.
The lot was certainly not cheap (in fact it nearly maxed out my credit card) but the coins averaged out to about $35; nearly all of the coins in the lot are $50-100 coins. Several (especially this and the Cilicia obols) are valuable enough I don't really know how to realize their potential. Maybe this one will show up at a future CNG or Heritage auction?