Just curious what populates the Halo 2 stats in the service record, if you can’t play Halo 2 online anymore since it’s an original xbox game?
Only those that played Halo 2 while the servers were online will have their stats tracked. Also, if you change or changed your gamertag anytime after the servers were taken offline, you won’t be able to resync your stats again.
Ah that explains why I don’t see mine, I have changed my gamer tag a few times since then, that was a long long time ago in a galaxy so so near. 
Oh well, bummer.