No... You are mixed up with the Nintendo Multi Connector...
SNES Multi Connector has the hardware inside for composite, S-Video, and RGB (NOT component).
N64 Multi Connector has the hardware for composite, but while it has the same connector, the American one does not have the hardware for S-Video or RGB (because S-Video wasn't popular at the time in America, and American TVs don't have RGB). Plugging in an S-Video cable will do nothing.
Gamecube Multi-Connector has the hardware for S-Video and Composite. This was the first time the S-Video cable was sold in America.
Component is NOT RGB. The Gamecube component cable plugs into an entirely different slot in the Gamecube. (They took the slot out of later Gamecube revisions to cut cost, and they stopped selling the cable, too.)
The extra slot in the Gamecube DOES have RGB, however. You can modify the Gamecube component cable to RGB and hook it up to a PC monitor.