I was surprised that the screenprint portrait of Mao Zedong by Andy Warhol, with two bullet holes put there by "Easy Rider" star Dennis Hopper was only estimated at $20,000 to $30,000. To myself I speculated that it might eke out a price over $100,000. I was not even close. The work with two bullet holes sold for $302,500 at Christie's on Tuesday, more than 10 times its high estimate. The 1972 screenprint from Hopper's art collection is done in hues of mostly blues and greens. Hopper shot the artwork when startled one night. He showed Warhol the bullet holes, and the pair agreed to consider the work a collaboration. Warhol drew circles around the holes, labeling the one over Mao's right shoulder "warning shot" and the one at his upper left eyelid "bullet hole." Another famous Warhol screenprint from 1967 of Marilyn Monroe fetched $206,500, or about four times the pre-sale estimate.