Buck Ghosthorse, the founder of this Ghosthorse scam, was born Leonard Albert Mattern Jr. in Pennsylvania. His ancestors look to be most if not all from Pennsylvania, back a century or so. No NDN.
He changed his name legally to Buck Ghosthorse (or Ghost Horse) in the 90s in Washington state. Mattern had already been presenting himself as NDN in Florida and elsewhere. Several of his followers, including Paul Sahayda, also changed their surname to Ghosthorse.
The followers who legally changed their surname to Ghosthorse were all adults when they did so. The claim that they were adopted as children by Mattern is false. The claim that Mattern is born and raised Lakota is false.
I hope folks read through this entire thread, especially earth7w's info, and elsewhere on this forum. The Buck Ghosthorse supposed lineage, including Paul Ghosthorse, is all fraudulent.
(Anyone interested can get a subscription to ancestry.com and pull together records, there are several people researching Leonard Albert "Buck Ghosthorse" Mattern Jr. already, some research is set as private, but with enough work his genealogy can be done.)