Wasn't that the whole point of the Libs blocking supply in the first place? They knew that a GG dismissal might be a chance especially with how on the nose the Whitlam Government was in London and Washington? That in itself is a political machination I would have though, playing for dismissal through the blocking of supply. A dastardly one at that.
I'm glad that, to the best of my knowledge, such a thing can't happen in today's Parliament.