According to schematics, all Macintosh II products (Macintosh II,
Macintosh IIx, Macintosh IIcx, and Macintosh IIci) have only the left
sound channel connected to the internal speaker.
(The Macintosh SE/30 has both sound channels connected to the internal
speaker.)
If any users ARE actually getting stereo from any Macintosh II system, it
has to do with software and not hardware. In all cases though, both
channels are connected to the external speaker jack, so external speakers
will produce correct stereo sound.