I believe the build dates for the series II start in Aug 03,you probably already know where to find the build date on the chassis plate?
an excellent site is:
http://www.users.on.net/~nweber/commodore/vy/index.html
as stated on this site:-
"Major changes introduced with the Series II include: A new high-output GEN III 5.7 litre V8 engine, producing peak power of 245kW @ 5,600rpm, is now specified on Commodore SS sedan, SS Ute, and SV8. Holden Calais and Berlina models benefit from a GEN III V8 power boost to 235kW @ 5,200rpm. ECOTEC V6, Supercharged V6 and GEN III V8 powerplants are engineered to meet strict new emission level requirements. 245kW V8s gain additional frontal rigidity from a strut brace mounted to the strut towers and spanning the engine bay."
So it sounds like most of the changes are found under the hood.Also noticed the series II 'S' came out with 17 inch wheels as standard too (as opposed to the 16 inchers on myn

)
If it has an earlier build date than Aug 03 then I would say that the dealer/car sales have mis-represented the car and so you should be entitled to some sort of deal.Here in NZ a dealer/car sales can get in a whole pile of do do's if the car isn't exactly the same as stated on the window card,don't know if it's the same for you guys??
& Sueme 82,the series 1 has cruise control and
all windows are powered so I'm not sure where you'd heard that they hadn't and were only introduced on the series II??