Pick vs Thumb 70's, 80's rock

I am sure I can do a search and get some info on this. I bought a DVD last week. "The Greatest Bass Riffs" and its very good the bass player is Craig Realley. There are 62 riffs on trhe DVD and I was suprised he played with his finger on probably 5 or so riffs and the rest witha pick. The riffs were songs recorded by The Beattles, Yes, Queen, Pink Floyd, Grand Funk, Led Zeppelin plus many others. Anyway just curious if most of these original artist used picks instead of fingers.

Thanks