Buying anything on Itch only gives you access to that version by default, but it seems the dev does give people access to the $5 versions at least for the next update when they buy the bundle. (So for this game 0.3.1.1 is out rn and bundle purchasers will likely have access to 0.3.1.2 and for the other game will have 1.6 and gain access to 1.7 later). But this is just speculation based on comments.