This one came up in July 2015 on Craig's List (Gulf Shores, AL, area) with an asking price of $1,800. Didn't sell at that time, and was put up again in January 2016 with the same asking price. Seems to be in decent condition, and comes with a CB pickup and one of the original rosewood bridges.
"1969 Dan Armstrong Plexiglas Guitar/vintage. This is an original Dan Armstrong ser # is in the first 500 of 3000. 2 pick ups / the original country bass pick up and another made by Kent Armstrong in 2007/rock treble. 1 extra bridge, 1 hard shell case. No texting, dealers or scams."
A460D is next listed on Reverb in March 2016 with an asking price of $3,200.
"Here's my '69 Ampeg Dan Armstrong for sale. It's a super cool guitar and I'd love to keep it, but recent circumstances dictate otherwise. The guitar is in very good condition, and completely original apart from a toggle switch mod. It's also currently got a non-original bridge in place but the rosewood one is also included in the sale."
"Also included in the sale is an original 1969 Dan Armstrong "Country Bass CB" pickup plus a second modern-issue Kent Armstrong "Rock Treble" (RT) pickup (currently installed). Comes with a non-original, 70's style hard case. Priced to sell at $3200 (or near offer) + shipping."