I was there about a month ago. I asked one employee where the exhibit was, and she knew about the cards seemingly because others kept asking, but not where they were. A second straight-up didn't know anything. So good luck, everyone! (It's level 1M, around from the stairwell, along the wall.)
This is ~1/3 of what's on display, which is way less than any of
us would want. (They had more room, too.) There are also some Cracker Jacks, Batter-Up cards, and of course Topps around the corner to the left. I've become accustomed to seeing $10,000 cards being better protected, but then I remembered there are several $100,000,000 paintings in the place. And there are no clues about the whole cards, but I didn't have a dying curiosity about what's on the back of
Washington Crossing the Delaware.