Bob,
It is not common at all to see a number like the 2455 on the ACC line. It is not a typical cryptic option code. From my experience with these cars, I"d say that is a COPO or F&SO order number.
As I stated before, information compiled by CHEVROLET CORP indicates 3 V8 '63 Chevy-IIs were factory built. Those are real documents.
Verne
