The 2-bass tune is "Love Your Life"... I saw the Soul Searching tour in 1976, Norfolk Scope (Wild Cherry opened). Hamish had a sunburst MM Stingray, Gorrie had a natural wood MM Stingray.
Check out the tune on the album. You can hear the 2 distinct bass tracks...a Mu-Tron pedal is used, as well. IIRC.