From what I can best recall:
81 and 40 game members were guaranteed access to buy strips which include the Futures Game, Derby, and ASG. 81 may have gotten their actual seat guaranteed, but I may be mistaken there. I know that's how it works for their playoff tickets. I am pretty sure 20 game members were initially only promised access to buy the ASG OR HR Derby. I remember this being the difference in me choosing between 40 over 20 for the 2019 season.
However, the additional strips did not end up selling all that well as I think they may have anticipated and I remember getting 2-3 emails about purchasing additional strips in the months leading up to that weekend. At that point, I all STHs had access to buy strips. But at that point, I imagine most of the 20 game members had already bought individual tickets or passed on the weekend altogether.