This 1971 guitar came up for auction in February 2009 with an asking price of $2,499. Single RB pickup according to my notes, which to me is one of the best pickups that they offered. Seems in decent condition, but perhaps someone has been overly zealous in screwing down the pickguard because two corners have broken off.
"This is a late 60s early 70s Ampeg Dan Armstrong Plexi Electric Guitar. This awesome guitar is in Excellent condition. It features a completely unique body that is made of an eye-catching clear Plexiglas material. The distinctive construction eliminates unwanted vibrations and frequencies, while producing tremendous sustain. The three-way switch offers multiple "presets" from a single pickup. The center position allows the tone circuit to be bypassed, while the other two positions allow the single tone control to affect different frequencies as the tone knob is adjusted. It has a hard maple neck and 24-fret rosewood Fingerboard. There is a small crack in the pick guard near the neck and a chip in the glass on the bottom left corner pick guard where the pick guard screws to the guitar. There are scratches on the body of this guitar. Hard-shell case is included. Overall this is a very good-looking guitar with some real character. This vintage Dan Armstrong is dripping with vibe and mojo! Don't miss out on this one"