I haven't seen anything like that in a true CRT.5 rim. There black spoked Traxxas Truck rims that will fit the crt.5, but they are 2" wide truck rims.
I have a similar question. My early crt.5 ARR pro kit came with two sets of rims. One set is the ofna crt.5 rim that uses 12mm hexes. They are easy to find. The other set was a bit wider rim that uses pins. I'd like to find more of these if anyone knows what rim they are.