Right
皮 supplies the sound - pí drifting to bǒ via the old p-/b- alternation, the same shift behind
波 wave,
玻 glass. The 'skin' meaning of
皮 doesn't contribute; it is a pure sound-tag picking up the lame-foot reading. Same phonetic series:
颇,
破,
婆 - all carrying a related pō / pó / pò syllable shape.