I did a forum search and couldn't find any threads that answer my question.
I received a set of meprolight night sights as a Christmas present. Looking at the package, it says they are for M4's built before 2002. Is there a big difference between pre-2001 sights and post 2001 sights? i.e. can I (or a good gunsmith) make these work, or do they go into the parts bin?