If Carmack obtained any sort of options or shares in Oculus stock prior to this deal, this is likely to be quite a hefty payday for him, no?

Just goes to show that his business sense was dead on, and he aligned his position with an organization he instinctively perceived as valuable before it's value exploded. It's probably safe to say, though, that his participation in the company also augmented the perception of its value, by his association acting as a defacto endorsement.