When is a 63 not a 63?

Nope, it's not a Polara or Polara 500. If it was, it would have a VIN starting 433 or 443 respectively.
You are right not a Polara 440 but the only difference would be trim level right? The sheet metal would be the same between Dodge 440 and a Polara. The Dart sheet metal is nothing like the Polara and Dodge 440. I had a 1964 440 Polara so I assumed in 63 a 440 Dodge would also be a Polara. I learned some new about the early Dodges. Jayson