Bobby Hart

Bobby Hart likely played an RMI Rock-Si-Chord on the Boyce & Hart album I Wonder What She's Doing Tonite. Hart is credited with playing piano, harpsichord, and organ on the album, and the signature RMI sound is prominent on several songs, including "Population" and "Pretty Flowers."

Additionally, an unidentified actor/musician can be seen playing an early RMI Rock-Si-Chord during Boyce & Hart's appearance on the television show The Flying Nun (Link). The episode aired on March 20, 1970 and featured the songs "I Thank You" and "Crazy Arms." The duo's cover of "I Thank You" was never put on a studio album, but the track also features a very distinct RMI keyboard sound. The instrument's three-tiered wood case was typical of both the Rock-Si-Chord and Explorer, however the green-ish hue suggests that this particular keyboard is a Rock-Si-Chord. Given the rarity of this instrument, I find it entirely plausible (if not likely) that the keyboard seen on this episode is the same one heard on Boyce & Hart's recordings.