First of all, about the tire with the injection dimple, once trued, the original, treaded tires will work fine; I believe they are the same compound as the slicks. Perhaps truing all the tread off will yield slightly more “rubber on the road”, but sanding them round will probably be sufficient. Neither will it be necessary to remove all traces of the dimple/injection. As long as the area around the imperfection is level it should be OK. You want to be careful and not over-true the tires; there is not much clearance under the chassis and you don’t want the chassis to drag.
On hubless wheels, where the set screw hole for the wheel is inside the width of the tire, requiring the edge of the tire to be curled back to get to the grub screw, I use a leather punch to make a hole in the tread of the tire. This does not affect traction.
I hadn’t realized there was a shortage of tires. Marty had the foresight to purchase tires for those in need. This is very much appreciated.
I have not seen the factory release for the #21 Andretti; the white kit version that I built may be sufficiently different from yours. If not, it might be necessary to put tape with a different number over the 21.