Right
卜 supplies the sound (bǔ → pū through b/p alternation). The traditional
撲 had a much more elaborate
菐 phonetic; the 1956 reform reduced it to the minimal
卜, which kept just enough phonetic match.
卜 itself depicts the cracks in a heated tortoise-shell used in oracle-bone divination; pure phonetic role here. Same simplified family:
朴 (simple),
仆 (servant).