Well, that's a drag. Thanks
@ads245 for trying it out.
Beyond the as-built data that you can pull from the Motorcraft site, all of which we've narrowed down as not being relevant, the only other lines of code I can find that seem to differ between my truck and trucks without DRLs are the following:
726-49-01 0101 0101 01 (DRL)
0101 0101 00 (no DRL)
726-59-01 50A5 195E
0000 0000
726-65-01 C4BE 35FF
0000 0000
726-66-01 C40E FCFF
0000 0000
I have NO clue what 59, 65, and 66 are all about, or why I have actual code there and the others just have zeros. My comparison was my 15 XLT against a 15 Plat and 17 Limited. The Plat and Limited were identical in their code beyond the Motorcraft data.
This leaves my last hope being 726-49-01, or it in combination with 726-49-02 as noted above, along with 726-11-01 and 720-02-01.