A bit older this time, perhaps
I listened to this version for the first time this morning: I had never heard this tune for the song before. Here is where we have want of a musicologist. On the face of it, it seems like this tune is less amenable to supporting instruments, so the other version may have taken hold as an adaptation. I’ll wager that this is at least slightly closer to the earliest versions.
The story here is more detailed than in the Garcia/Grisman or Mike Seeger versions–touching on some of the details referred to in the comments to the previous post.