Yes, it's chassis 948/5, one of three built in 1948 to compete in the Mille Miglia, which it did twice.
When bought by Perry Fina of New York he replaced the Alfa engine with a Cadillac V8 to make it more competitive with the big-engined cars in the US. Some say Mr Fina designed the body, but it is of course a Motto body, though perhaps Mr Fina made a couple of modifications to it.
The car was later restored and returned to original specification with its Alfa 2600 6C engine.
So, that makes you a Professional now. Believe me, life gets a lot harder from now on...!
Congratulations anyway!