Welcome.
Rare coin indeed, Ferrando records this coin as unique (2003) for the the 2nd officina (414) and R1(2-3ex.) for the first one (413). I can't see in which officina your coin has been struck.
Note that there must be an error in Ferrando's book as he describes the obverse legend with a N-S break and show a coin with a S-T break.