I believe why they are both floating calipers the mounting plates are slightly different. The front suspension geometry of the 2nd gen Tacoma is similar to an FJ/4Runner. But I believe the Tacoma might be a hair wider frame wise or something as the sway bar is a much different design and some of the parts are not in fact compatible.
While the Tacoma, FJ, and 4Runner share the same platform, they did play with parts and adjusted the frames between the vehicles in a way that not everything is a direct bolt-on swap. The FJ shares a more bolt-on friendly suspension/driveline than the Tacoma, partially because the Tacoma was designed as a truck and so they went that route in design; rear leaf springs, slightly modified frame, ect ect.