Indeed!
The mysterious denomination of this car seems to indicate that it was originally a 1979 3rd gen Quattroporte (codenamed Tipo AM330), which was rebodied and converted into a coupé at some point by ATL (Autotecnica del Lario). Strange, because ATL reportedly had already folded in 1976, according to the info available on the www. It's very confusing. If anyone has more info that can clarify what this car is, it will be very welcome.