I think it sounds like your friend is confused. The US90 was more or less the first ATC in America which later became the ATC90 then the 1979 ATC110. He could have been talking about some of those oddball centrifugal clutch driven 4strokes that were around but surely he would have explained the difference to you.
See here for the Cliff's notes on the history of the Honda ATC/V: http://www.atving.com/editor/feature/atvhistory/hondahistory.htm
P.S. Where in Illinois are you? There are a couple of us Illinois Boys here now. :-D
• Rebuilt '79 110
• Rebuilding '82 200