The CO2 has displaced any usable oxygen so there is not much for molds to survive on. It will not spoil, especially in a vac bag, so give it a shot & let us know.
I think of a Swiss as a balloon full of young, gas producing cheese. As long as the "balloon" (the rind) is intact, the gas inside tries to move around, pushes on the cheese mass, and make little tunnels - eyes. It is critical for the rind to be pliable to allow for expansion. Francois suggests using a PVA coating. I personally only do a VERY light brining so the rind stays pliable.
However, if the balloon pops or is broken in any way, the gas will take the path of least Resistance and flow outside of the cheese instead of making eyes. Depending on timing, you may get good eye formation before the gas starts to leak thru the rind. So, if you get really good swelling before the leak, you may still have a great Swiss.