Well not exactly. You have to make one or have someone make you one. It's basically a 11.5mm square with a 4mm hole in the middle. Everything stays in sync as the cam is secured to the axle.
Lou in reading this I figured you likely make these from brass stock, but why couldn't they be 3D printed? The design is easy and you could print them several at a time, and once cured the resin becomes hard like glass. Here's a snip of the simple design file I came up with:
It's basically 11.5mm to a side, 5mm thick, with a 4mm hole as you said. I also radiused the corners to 7.6mm just to make life easier for the cherry switch activation lever. This gives a net switch stroke of 1.85mm which should work fine. If the corners were left not radiused the stroke would be 2.38mm.
I think it would also work if made in 2 pieces, and CA glued to the axle shaft in place in the truck. That would be way easier than disassembling the entire truck and having to re-quarter the drivers to put it back together. What do you think? Of course you still have to remove the old 2 lobe cam somehow I guess.......!
Rod