There is a tidbit on this topic in "Dark Star: An Oral Biography of Jerry Garcia"Tennessee Jedi wrote: Yo Banjo man
was that Jerry playing banjo ?
Go to this link and then hover your mouse over the book cover in the top left to get the "Search inside this book" window to appear. Type in "121" to go to page 121 and read the David Nelson entry.
That's my best guess as of now. Maybe someone else has other proof?
http://www.amazon.com/Dark-Star-Biograp ... 979&sr=8-1