Something on here nagged at me. It's stated in the tree, and at other places on SB, that there's only one Beam rye mashbill, but I knew I'd read or heard somewhere that Beam rye and Old Overholt were different, and I finally found the source: Jim Murray, in his book The Complete Guide to Whiskey (Triumph 1997), states:
. . . Jim Beam's is 51 percent rye. The big boy is Old Overholt with an impressive 61 percent rye.
Now, that was at least 15 years ago, but Old Overholt was established as a Beam product at that point, and he must have gotten that information from somewhere.