If it includes the Holeshot mid-pipe - as it did when it was new - it WILL fit.
It's cans that bolt onto stock mid-pipes that don't cross generation lines - that and the '04 has it's mid-pipe welded to the stock can, so they have to use an aftermarket mid-pipe - or cut the stock can off the stock pipe. But it's better to get a can with a mid-pipe cuz the OEM mid-pipe is restrictive anyway.