Yes, MUDs are more "stat" and "game" oriented. MUSHes are more "story" and "roleplay" oriented. That's not to say that there are not RP driven MUDs (though they are generally rare), nor that there aren't "stat" and "game" driven MUSHes. Most of the MUSHes I played back in the day had very well developed character and combat systems imported from popular table top RPGs. Some have even had advanced flight and travel code allowing 3D spatial starship combat in real time. So while the codebases can be defined, those definitions are not ironclad.
And its cool to see some old SW:MC names, I recognize them and that's kind of scary after all these years. =)