They just mean is it a base model or GT model to order the kit, I hope. There is really no difference in the labor, unless they are just thinking they could charge you more because you have a more expensive model. There are different clutches and flywheels specified for the different models, but it actually looks like they might be interchangeable based on the specs. I paid about $86 for a new Exedy clutch kit, and got a pre surfaced GT flywheel for about $42 on Amazon. Along with the other expenses, Pennzoil Syncromesh manual trans oil, new flywheel bolts, etc. I spent about $200 on all the parts. My clutch change thread:
viewtopic.php?f=12&t=43780&p=504322
Looks like the kits are the same price for either one from
http://www.rockauto.com
EXEDY Part # KTY03 One of our most popular parts
Base Model; 5 speed trans.; Disc mm 210; Disc in 8-1/4; Splines Dia 1; Splines 21
Part Image
$85.79
EXEDY Part # KTY14
GT Model; 6 speed trans.; Disc mm 210; Disc in 8-1/4; Splines Dia 1; Splines 21
Part Image
$85.79
I would make sure the shop puts in a name brand clutch, or lets you buy the parts to have installed. The PO of my GT had his done about 1-1/2 years before I bought it from him, and the shop put in a cheap Seco Korean clutch, and charged him about $1,400 for it all! It went out after only 12,000 miles. I think they charged him like $326 for the clutch kit and $40 for flywheel surfacing, $300 for the clutch slave cylinder and master cylinder, and the rest was labor.
Good luck!