I don't think it should really make a difference, but what class were the tickets booked in? Were they true F, A, or P? Or was it one of the instant upgrade fare classes, with status, which would have booked into U?

Either way, once confirmed in first, you shouldn't be bumped back at the gate, except in the case of an FAM or I think sometime an on-duty deadheading pilot (onwards to a duty day) which is contracted to be FC. (I seem to recall that was a thing.)