your gun is a 2004. thus a pre-2k kit will not fit as the banjo bolts are different sizes. those terms "pre-2k" and "2k+ (2000 and later)" refer to what year model guns they were designed for, not when they were made. youll see it a lot in cocker lingo. otherwise almost any part from any cocker is interchangeable with another with only a few exceptions.
youll also see pre 2k and 2k specs again on bolts too, as the pre 2k ones are longer and need a pre 2k back block to fit. however you can put a 2k+ spec bolt on a pre 2k gun as long as you use a 2k spec back block too.