i looked into this about as thoroughly as i could.
the only 14x7 amc steelies were the 'turbocast' rims with the styled urethane molding. they would probably take a full wheelcover but not a hubcap even with the urethane removed. it'd be nice to find i was wrong though.
Big disappointment! Somewhat surprising, even. So even cop cars didn't get wider wheels? Or maybe the situation changes with 15"