This one arrived in the mail today. A Roman antoninianus, its my third of this emperor. Minted in Rome. Gallianus 260 - 268 AD Reverse has Sol with a globe ID - RIC 160 :hail:
:smile Thank you Arda, I will research the reverse again. I guessed it was a kind of SMT (Sacred money T).
RIC attributes this to the Milan mint. I presume Gobl does the same, though I do not have that volume at home to check. Mintmarks weren't truly standardized until Diocletian's reform.