On
antoniniani of
Gordian III the
bust right seen from front was never used at
Rome and is very
rare at
Antioch. The usual
bust type on
antoniniani at both mints is
radiate, draped,
cuirassed right, seen from back.
The
CONCORDIA AVG type coupled with
bust seen from front indeed seems to be a new variant, not recorded by Roger
Bland in
his dissertation.
RIC, on p. 33, is not implying that
bust type b is any different at
Antioch than at
Rome, as Jochen suggests; the meaning is rather "
bust variety b appears here just as at
Rome."
I commented recently elsewhere that Cohen's descriptions never distinguish busts seen from front and those seen from behind: for example what he calls "
bust radiate, draped,
cuirassed right" can be either the variant seen from back or that seen from front.
RIC, in its earlier volumes, tends to follow
Cohen in not distinguishing these two forms.