I might have wrote off that stand theory a little too fast. There was once, in the early 90's, when I had a shop give it a complete overhaul. I didn't like their work (reputable shop, thou) and he convinced me to ditch my GEL 280's for some clinchers. Bad move. I believe he swapped hubs on me as well. That being said, there is the spot at the lug and the dimples are on either side of the point on the lug. I'd take a picture but the seat stays block the view. I can't imagine a stand clamp fitting there.

Also, I checked for corrosion. I don't see anything that looks abnormal, not that I've looked inside this frame very often.

Again, thanks.