It's largely irrelevant. In the face of lack of confirmation, you discount the value of any shares or options accordingly. The first thing I make clear when negotiating is that unless they can prove otherwise, my assumption is that the value of the shares they offer is near zero. If they want me to consider them worth anything when assessing the value of the total comp, it's on them to demonstrate that they are. Otherwise I will expect a salary that reflects a value of the shares near zero.