“The first acoustic you could plug in”
Is that correct? There were acoustics before 1967 that could be plugged in I’m thinking.
Not straight acoustics. Hollow-body guitars such as Guilds, Fenders and Gibsons still used magnetic pick-ups.
Ovation invented the underbridge pickup that used piezo crystals to directly 'read' the vibration of the strings and bridge, which gave the Ovation the acoustic sound.
Glen Campbell was one of the first artists to popularize the Ovation guitars on his Goodtime Hour. He collaborated with Ovation to fine-tune their guitars.