Identifying This Roman Bronze

An unremarkable and totally unattributed 4th century coin just picked up on the cheap. About 17 mm across. Somewhat encrusted, but I actually like its presentation. My initial impression (and I continue to hold this opinion) was that it's an issue of Constantius Gallus, who for whatever reason I've never had one of before. I think it was struck at Heraclea with a mint mark of SMHB, but if so I haven't yet found a precise catalog match for it. My thought is that it may be a variant of RIC VIII 87, although I'm not seeing the field "Δ" on the obverse that's associated with that entry.

Yes, I recognize it's by any measure an inconsequential coin, but I'd like to know if I've gotten my identification anywhere near correct (it certainly wouldn't be the first time I've misread a mint mark).