Your dealer is either nuts,trying to get over on you or doesn't know Vettes.Yes your roof will work.No difference in them at all.
It may interest you to know, that GM just started a new incentive program for all Grand Sports, and ZR1 vehicles delivered between Jan. 3rd, and Feb. 28th, 2013, that entitles you to an additional $2,000 instant cash back....I received a voucher in the mail for $1000 off the car when I sign the deal...
If you need proof, just go to the GM site, then "Build Your Own".thanks for the heads up - saw nothing on the website BUT will continue to look....