Any reason not to let Firestone mount my wheels?

[tga]

The biggest potential issue is if they don't know to remove the bolt that (unnecessarily) holds the rotor to the hub, you could warp your rotors over time. If your new wheels do not have a cutout for that bolt (most don't) you can simply remove it. If you don't remove the bolt, your wheels will not sit flush on the hub. Some people shave the bolt down, but that is a waste of time. Just remove the bolts and save them in case you ever want to reinstall them again.

Functionally they don't do anything since the wheel / lug nuts hold your rotor to the hub, not that little bolt. It's just there so when the brake assembly is put on your car at the factory the rotors won't fall off the car as it moves down the line without wheels on it.

- - - Updated - - -

Here's a picture of the bolt (screw?) for reference.

View attachment 104545

What's the issue? Is the bolt not countersunk so that it's flush with the rotor surface?

I've seen these on a bunch of european cars (Porsche, Audi, BMW/Mini), and they are always countersunk with the surface of the bolt at or below the face of the rotor. I've never seen them interfere with any wheels, stock or aftermarket.