interchangeability of exhaust 99/00-01/later

As I understand, when looking for a replacement muffler the 99 and 00 sprint ST's take a different application than 01 to 04. Will an 01 to 04 can work for a 99-00 bike? I'ver heard the main issue is the later bikes have an oxygen sensor as part of the mechanism and the 99 and 00 do not have this so obviously you couldn't use a muffler that is not equipped with an oxygen senor on a bike that requires an oxygen senor but is the same true for using a later model muffler on a 99/00?

Thanks for the help.