From what I understand the kx500 pipe fitting is all the same from 1988-2004. FMF for example are sells a pipe that fits all those years. Kawasaki on the other hand has two part numbers for these years. The 1988-1996 is a 18002-1862 and the 1997-2004 is a 18120-1094.
What I am wondering is whether there is a dimensional difference that changes the tune between the two Kaw part numbers or are the two numbers just paint, finish or paperwork change?