Not quite, A.
5800, 5900, 5950: 4x2/8x0 (the latter is for stencil/z ops, as in the shadows in Doom 3).
5600, 5700: 2x2/4x1(/4x0?)
5200: 2x2(/4x0?)
So your 5900SE has four pipes with two texturing units per pipe. You don't multiply pipelines by textures per pipe to arrive back at pipelines, but you can say that 4x2 (FX 5900) is about equal to 8x1 (Radeon 9800) in heavily dual-textured games. The 5900 can output four dual-textured pixels per clock, while the Radeon can output eight dual-textured pixels every other clock: same difference. The situation changes in games that have more odd-numbered texture layers, or that have more shader ops.
Edit:
A nice table with pipes and fillrate. I'm almost certain 5200 is 2x2, though. If you're really curious, you could look into old reviews that have 3DMark fillrate numbers.