Chevypower,
Welcome to the forum!
The GS cars started production in Jan. 1965, so that really can't be a GS body with that trim plate and VIN tag.
I know there are a few 65 Gran Sports with 08 (August 1965) build dates, but the body number would be much higher
as you would know. Since it is a 44467, that body style is easier to replicate as a GS as it already has the convert
frame that all GS body styles used..
Some pics of the trim plate, codes on the trans and engine, etc. would better help solve the mystery.
Mark