Chevrolet Motor Div. hopes to beat Ford Div. to the market with pickup trucks equipped with side-access panels, or so-called rear or third doors. But even if it doesn't do that, the division isn't adverse to attempting to upstage Ford in its own territory. Chevrolet, and sister GMC Div., display both their compact and full-size pickups with the side access doors deep in the heart of Ford country. Rear-panel Chevrolet C/K and Blazer pickups, and GMC Sierra and Sonoma trucks, were shown at the Hyatt Regency Hotel in Dearborn, MI, across the freeway from Ford's world headquarters. Was the act deliberate? "Yes. Absolutely," says Bill O'Neill, Chevrolet's general director of communications. "It's the third time we've done this." GM starts building the rear-panel trucks - legally it can't be called a door because there's no exterior handle - at year's end.