In September of 1976 Adamas (the elite guitar side of Ovation) introduced a prototype (pre-production) guitar for performing artists and select dealers. A total of 34 guitars were built, starting at 27 and ending at 60. They were sent to the likes of Paul McCartney, Cat Stevens, Neil Diamond, and Nancy Wilson to name a few. Glen received the very first one, #27 in August of 1976. At some point, Glen gave the guitar to Carl Jackson, Glen's bandleader for 12 years, where it resides today. You can see some of Carl's videos on his Youtube Channel.
Here is a video of Glen playing this rare guitar, which is rich with Ovation and Glen's history.