Yes and no. If the valves are closed or the ports are blocked off then no fuel would be going in, but that's another mystery to the story If it was true, then how was it done?
The fact that the engine should should have low oil pressure and possibly fuel going into the oil would and should debunk this myth, but I have heard and know how it could be done with those issues fixed. That would mean it was a dealer inspection test car engineered by GM if it was true.