Something doesn't sound right...
When my unit prepped for deployment the unit paid for Class 3 and 4 dental work. You only had to do some paperwork through S1 or the UA to arrange the appointment. We really didn't worry about Class 2 (since I think that still falls into the "deployable" cat). Anything that isn't done prior to MOB site, will be done at MOB site, if it places you in a non-deployable status. Getting it done at MOB site may force you to deploy late and join your unit downrange.
Perhaps your 1SG is not aware of programs available to his Soldiers yet. I know we had MEDPROS at our drill damn near every month drawing blood, giving us shots, doing checkups... all prior to MOB site, prior to SRP even, just to be sure everything was caught ahead of time so no one would get stuck at MOB site, or needlessly kicked at SRP.