I would be willing to accept the
obv. as a possibly official die, reading
PERT as normal in the
legend, and
COS I, provided that the silver content of the metal looks normal and is not obviously debased. What are the
weight and
die axis? However I do not appear to know any other coins from this exact
obv. die.
The
rev. die is cruder, and has the mistakes of V for F and
Fortuna facing the wrong way, but I wouldn't entirely exclude its also coming from the official
mint, at a time early or late in its production when practiced engravers were not available.
I gather that one cannot make out whether
Fortuna is holding a rudder or a branch?