'thrillathahunt',
Fair question. Kenneth Edgett, of Malin Space Science Systems, San Diego, the principal investigator to the MAHLI project gave this answer; “Originally the Curiosity rover was going to launch in 2009, and so I had planned all along to use a 1909 cent in celebration of the centennial of the Lincoln cent,” he said. “I could not use one of the four 2009 cents because we had to commit to the design and materials (i.e., the 1909 is brass, 2009 is mostly zinc) in 2008. When the launch was delayed to 2011, we still went forward with the 1909 cent because we already had it in-hand."
Don........