This guitar came up for sale in June 2013 with an initial asking price of $1,850 and finally sold for $1,500. That seems right at market, single RT pickup and missing the pickup thumb screw. Otherwise nice example. Here's the seller's description:
"Up for auction is a vintage Dan Armstrong Ampeg Acrylic body electric guitar. The serial number is A962-D which based on my research indicates a 1969 manufacture date. From the research it seems that only 3000 each electric guitar and bass were made. This instrument has been used and shows some surface scratches on the body, only one which is clearly evident and some rub marks again from use. There is a little rust on the cord jack. On the back of the body it appears there is a missing screw which may anchor the pickups.The back of the neck has some finish wear."
"This guitar features the acrylic body, quarter sawn maple neck, Brazilian rosewood fretboard, 24 frets, formica pickguard, 3 way switch, master control and tone control. It also is equipped with the RT (Rock Treble) resin pickup. These pickups were interchangeable. The tuners are Schaller made in West Germany. I am told that this unit has 24 3/4" scale length and 12"fretboard radius. However, not being a guitar expert, much of this information comes from my research. The hard case in in good shape but I do not have a key for the lock and just use the snap locks. The interior of the case is fine but the outside shows use."
"Please feel free to ask any questions and we will do our best to get you the answers. Pics attached. First time bidders should contact us prior to bidding or risk having associated bids canceled."