The answer to your question is NO. I had the same question and couldnt get anyone to answer it... so i tried it.. lol. Wish it did work cause it would solve alot of problems.....
I ended up using the complete XB forks. As upthemaiden said, the 03/04 forks are 41mm and 05+ are 43. The 03/04 forks will fit the X1 triples... BUT to get the forks located in the correct place for clamping, the top of the forks stick above the top triple about 3 inches. This causes 2 problems... it lowers the front of the bike, and it does not allow for your handlebars to bolt on even with spacers. Couple ways around this... switch to clip-ons or get 3+" risers, or use XBs triples.
The XB triples lead to more problems... the XB stem is about 1/2 longer then the X1. I believe ophawk made a lower spacer (still not sure how cause i tried it and didnt seem to work) or press the XB stem out and the X1 stem in.... If you do this, you will need to machine a counterbore in the bottom of the lower triple and replace the top bolt, or counterbore the top triple hole out larger like i did to use the original bolt....
Another problem is by using the XB triples is you loose tight spot turning because of 2 reasons... the fork location is different on the XB and the upper triple hits the tank!
But the look is well worth it! haha. I havnt ridden mine yet since im still working on it, but cant wait to finish it up.
XB triples with X1 stem
XB underside lower with counterbore for X1 Stem. If you dont counterbore then the X1 stem is 2 short because the XB lower it thicker then the X1 and the X1 has a counterbore also.
counterbored XB upper to accept the X1 top bolt.
Also, i got my 03 forks on ebay for a whooping $108 and the 03 XBS triple for I think $80. I dis-assembled them and powdercoated them myself, and put all new seals in them.