HELP! Need information on Shotgun

I have an Armalite AR17 12 gauge 2 shot auto. Aluminum barrel and action, stock all plastic approximate weight 4 pounds. The only information I have found was on the armalite history web site. It was manufactured sometime between 1956 and 1962. Supposedly they made enough parts for 2000 guns, but only produced 1200 finished guns. Would anyone know where I could get parts and/or a manual. I'm also interested in it's value. Any information would be appreciated. Thank You 250