Apparently this
sestertius is commoner with TR P XXVI than XXVII.
TR P XXVI: 3 spec. in BM, all
Germania seated l.,
var. with
Germania seated r. mentioned in note.
TR P XXVII: BM 1432 with
Germania seated r., 1432A (acquired Münzhandlung
Basel, 1938) with
Germania seated l. as on your coin.
The exact date, and whether
Germania sits l. or r., will hardly affect the market value of the coin however, since most collectors of ancients are not aiming for completeness so won't pay extra for mere
rare varieties.
It's not quite right that your coin is
not in RIC. The main purpose of the early volumes of RIC was to rearrange
Cohen chronologically, so barring slips anything that's in
Cohen will also be in RIC.
Cohen 217 was indeed taken over by RIC 1049. The only difference to your coin is that
Cohen says
Germania is surrounded by shields. But I wouldn't consider the addition or omission of
weapons in this
type to be a deliberate variant, just something that some engravers added and others didn't. So your coin can be called
Cohen 217 = RIC 1049, adding "
var." if you like.
The
Glasgow catalogue does not give the wrong references for their coin corresponding to yours: the footnote to 183 says "Cp. C 222, RIC 1054,
BMC 1432 (but
obv. head laureate r. and
rev. Germania seated l.)". So Miss
Robertson specifies how the
Glasgow coin differs from the numbers she cites. It would have been better, admittedly, for her to cite
Cohen 217, RIC 1049, and
BMC 1432A, which are exactly like the
Glasgow coin, except for the shields around
Germania mentioned by
Cohen and RIC.