I was in the Navy and I was never in the height/weight standards. They just measured my neck and then my waist, so I was able to pass after that.
Linemen at non-service schools have a slight advantage because they can spend an offseason just simply bulking up, if they want to do that. The service academies will have to make sure that any size they put on is very lean. They have to maintain some cardio also. Most of the big dudes you see around the country have no real cardio. They can just concentrate on getting bigger