It depends on the circumstance.
In an obvious pass rushing situation guys like Fergie and Hand can often be handled 1-on-1. They are great at controlling a confined area and shedding blockers to make plays in the running game but they are usually not great at beating 1-on-1 blocking in the passing game where quickness is more vital. They may contribute every once in awhile with a great bullrush but this does not happen with regularity.
However, if the pluggers can control two blockers on running downs and control the middle, this gives a guy like Glover more license to try and get after the QB knowing his buddy is taking care of the running game.
I suspect Fergie will get a fair bit of rest when the nickel D is on the field and Glover will probably get a fair bit of rest in the 3-4 alignment. It will make both players better over the course of the game and the season.