I had a red Slotmaster controller in 1967-68. It wasn't transistorized but I think the black and gold ones were. I didn't buy it new, but I forget what I swapped for it. If memory is right, the transistor models were about $25 back then.
Jim, as Jay said, could you show us photos of the chassis and motors of these cars? Some of us would find pictures of the slot box they're in interesting, too. You got a nice collection of vintage cars that have seen some track time. When I began commercial slot racing, all the raceways in the area mandated the use of silicone rear tires, so I'm somewhat familiar racing on them. Tracks have to be squeeky clean and they don't mix well with other types of tires.