Yup, a standard model 2 -> SCART cable would pull stereo directly from the A/V jack on anything except a Genesis model 1 or model 1 w/32X. I only mentioned my cable setup because it covers all variations including Genesis 1, PBC, 32X, or newer Genesis consoles with one common SCART cable.
Whether you'd want to use separate L/R plugs on the Genesis 1 instead of the headphone jack->SCART depends on what you're doing with the SCART output. I'm running all my RGB consoles into SCART switchers, so I wanted to standardize with audio on the proper SCART pins. If you wanted to run audio directly off your Genesis 1 that should work fine but you'd probably need to swap audio wires whenever you changed to the CDX or other consoles.
I'm in the US, running an NEC XM29 RGB monitor. 29", 4:3, RGB, CRT, 15kHz consoles/DC VGA box/480p, and tateable!