'68 bass technique

[Jeff House <jjthandmeh@juno.com>]

I have always wondered where the sounds come from on some of the live
recordings I've heard from the late '60s.  It sounds like there are 3 guitar
lines in spots.

This morning I was listeneng to MLs "Stages".  I think "Little Billy" and
"Relax" come from Filmore '68.  The 3 guitar lines are particularly
pronounced on "Little Billy" where I hear all 3 through the entire song. 
"Relax" has them in sections.  I hear rhythm/lead (Pete), a melodic bass
(John), and a rhythmic bass (I presume it is John too).

Was John using a technique that produced two bass lines then?  Possibly the
rhythm with thumb and melody with fingers.

Would anyone care to tell me I am hearing things in my senility and burnout?
I often get the feeling listening to the Moon-era live stuff that there are
more than three instruments.

Jeff