How can that be? The districts were redrawn for the 2002 elections and GW Bush did not run in 2002. There is no way to know how the people in new district voted in 2000 unless you somehow knew the address of each person and how they voted, and nobody knows that.
They have all the statistics. I'm sure they're in the almanac of American politics. You just match up precincts from old to new. If precinct lines were redrawn, that could be a problem, but that's generally not an issue.