That poor bassist didn't have a chance to vary! As did Mo Foster (whom I rate highly)
as the melody is/was composed by the late Herr Moore and he was always adamant that things are played his way (as many bassists with him - Neil Murray, Bob Daisley, Glenn Hughes to name but a few - have confirmed with a tired shrug). Still, bass solo is bass solo, guitarist-written or not! Most guitar solos are composed these days and nobody gives a flying f***.
My guess is though that Moore was more than a little inspired by what Roger Glover did on MWFT, 3.00:
He has meanwhile varied it somewhat and Herr Morse has given it a country influence too it, 3.08, diese Amerikaner: