I was looking at the same sort of thing when I had my ep3.
From the info I had, the only way you can split seats from rails is if you have the type r seats you can remove the fabric on (zip on the back of the seat to confirm) somthing to do with early ones without the zip/removable fabric don't split from rails prefacelift ones mainly. your after late spec facelift+.
My 04 plate had em.
Hope this helps Dave.