TV shows then always depicted kids as listening and dancing to early-60s type surf-guitar-ish instrumentals all the way through the 60s, when that was hopelessly out of date by 1965 or so. My latest thought on why they did that is that records with vocals would interfere with our hearing the dialogue.
Good point, also might have been that hack guitarists willing to lay down some surf were a dime a dozen in the 60s. I think the premiere of Doctor Who featured his grand-daughter or some other school kid with a transistor radio gyrating to some surf guitar -