This coin is not in RIC VII, but should come after RIC VII Trier 381. There is an example in Die Bronze-Teilstück Prägungen der römischen Münzstätte Trier by Zschucke from the second workshop-- RMBT 13a.
This coin may have had some tooling, as the arm position looks odd and the fields seem to show evidence of smoothing. This makes it hard to be sure about the bust, as RIC and RMBT have cuirassed only, but this example seems to show some drapery.
The shield also has an elaborate scene. RMBT lists 42 different types of shield decorations from Trier and this one is #40. It is described as Constantine I with a soldier nearby, being approached by Constantine II, in a position of deference, with an attendant/ soldier.
Constantine II
A.D. 321
19x20mm 3.9g
CONSTANTINVS IVN NOB C; laureate, draped and cuirassed bust left, decorated shield on left arm, holding horse by bridle with right hand.
BEATA TRAN- QVILLITAS globe set on altar inscribed VO/TIS/XX; above, three stars.
in ex. PTR
RIC VII Trier --; RMBT 13a
