while GL is certainly 'paydirt', and important, what about other plays where we have short yardage? - I would speculate 'no'.
Our Umpires do not yell out anything unless the ball is in the endzone. All those calls are the wingmen calls.
If an umpire sees a fumble in the field of play, he throws a bean bag. And the umpire only whistles in a couple of live ball situations. When the umpire clearly sees the ball carrier down, and he has been down for a second, and no wingmen know where the ball is, the umpire will blow the whistle.
For passes, the umpire normally does nothing, except move up to the line of scrimmage. But for quick passes over the middle, the umpire, if he can, will pivot around to watch and see if the ball is trapped, or bounces from the turf. In those situations, only, will the Umpire blow his whistle and signal incomplete.
Are these not normal things, or only in our area?