Hello Mr. Mesher,
Seth here. The GHI/BeagleBoard.org Capes should work out of the box. Those .dts files and such for making files available are past tense, sort of. W/ the new image, the config-pin utility exists. You may want to update your BBB or variation w/ the 10/2018 IoT/LXQT image from bbb.io/latest-images
. They have a SD Card image on those pages.
U-boot overlays is a thing now. I think people have shied away from .dts files due to the complications and lack of updates from TI.
P.S. There are no .dts files for the GHI Capes from BeagleBoard.org. Everything is done w/ EEPROM. You can find that info. online. GitHub.com has a repo dedicated to the EEPROM on those and you can find additional info. here at this address: https://github.com/beagleboard/capes
. Further down that page on GitHub, you will see that most of these Capes from GHI are prototypes or in development right now. They are for us to use and learn from I guess. I will wait until the other "production" Capes come out, too, when I purchase another couple. I hope this is some background and present info. for you to review. Oh and those Capes from LogicSupply are out of my league. I know nothing about them as of now.