Carry on reading the post.At this point I'm going to say you are talking exclusively about WotC-D&D. As a triviality Comeliness was a seventh stat in the original Unearthed Arcana.
More importantly d20 + modifier vs target number only became the core mechanic with 3.0. It was a mechanic before that - but there was also roll under your stat, roll over your savings throw, system shock and thief skill percentiles, and however initiative worked. When you seem to have excluded AD&D from your D&D variants I'd say you have cut far far too narrowly.