I don't think they are. The blades on the tamiya are generally a lot smaller. The "ball" at the end of the driveshaft is also much bigger on the HB driveshafts. The blade must be bigger to accommodate this. Tamiya blades would be way stretched out on HB drivshafts, and HB blades would just flop around everywhere on Tamiya driveshafts
-Korey