Nero introduced the
radiate crown on bronze coins of the living emperor, and a little later began to use it as a
denomination mark on
his dupondii.
But the
radiate crown was
still a divine attribute, so
Galba and
Vitellius omitted it from their
dupondii.
Vespasian too at first omitted it, but then brought it back to mark
his dupondii, apparently from early in 71 on.
So your coin could be a
dupondius dating from early in 71, before the re-introduction of the
radiate crown on that
denomination.
To confirm the color of its metal, I would recommend placing your coin
side by
side with both an unpatinated
red As and an unpatinated yellow
dupondius or
sestertius. I have found it easy to make mistakes when trying to judge metal color from just a single coin, without comparison to other coins whose metallic composition is certain!
RIC makes several attempts to separate
asses from
dupondii among Vespasian's early middle bronzes, but without making it entirely clear what the correct order and chronology of the various issues was, and when the
radiate crown was re-introduced. In any case the latest
dupondii of 70 AD were apparently
still laureate:
RIC 36-38.
A third peculiarity of your coin:
VESPASIANVS not just
VESPASIAN in the
obv. legend.