I don't know for sure if the spacing changed, but I believe they went to a larger diameter fork in 03 as well as different triples. I know that doesn't help, but it's all the info I have for your situation.
I am sure that the front spacers are the same. I used my 01 YZ250 Zipty spacers on my 07 YZ450f. 95 % sure the back are the same. Part numbers are screwwy, but somewhere in those years, the spacers changed to coming with plastic shields instead of bare spacers. WD