There's two lessons learned here.
1) Never take your vette to a general shop, beit local or national chain. They have very little respect for their greasy hands and even fewer, if any of their guys, have worked on cars as old and as "different" as yours. I don't even take my daily driver to 'em anymore because there'd be grease all over the steering wheel, door handle, etc.
10:1 odds they didn't align the rear because they either didn't have the proper instructions for doing it, they didn't have the proper shims for doing it, or they couldn't break the bolts free without possibly breaking 'em.
2) When you are going to have tires done on the vette, just take them the tires. It's a pain, but find a way to get just the tires up there. I borrowed a friend's truck. And be sure to tell them ahead of time what exactly you want. E.g., no weights on the outside lip, put them on the inside and flat weights on the inside wall if they need to be as close to the outer lip. Be very specific that you want your chrome caps and valve stems back on. Don't let them BS you. YOU know your car. The grease monkeys wrenching on it and the manager don't. And they are used to customers not knowing their arse from a hole in the ground, so they stick to their guns as a way to make you doubt yourself.
We've all been there. One last thing... the alignment shop should ALWAYS give you the specs of the alignment they did so you have a reference point.
I know Warren is a bit far out, but if you want it done right by people that respect your car, take it to Backstreet Performance in Medina. That's who did my car and that's where I'm also going to dyno my car this weekend. In the 11+ years I've had my car, it has NEVER driven as well as it did after they aligned it last year! It's phonominal!