I've never heard of double point, but there is a Double Star. Double Star is a spin off from J&T Distributing, which has been in the AR business for 20+ years.
Sounds like the gun shop may have ordered complete DMPS lowers and then ordered some Double Star uppers and put them on the lower. It only takes 2 pins and about 30 seconds to put an upper and lower together. By ordering uppers and lowers seperately, you avoid the 10% FET that is paid on complete firearms. What I would suggest is to look at the markings on the barrel. Usually on top of the barrel, in front of the front sight post, there is markings on the barrel showing if the barrel is chambered in 223 or 5.56 NATO, if it is MP tested, and if it is chrome lined. A 5.56 chamber is preferable to a 223 chamber, as it would be safe to shoot mil-surp ammo in it. Also, Double Star in general doesn't chrome line the barrels, depending on if that is important to you. At that price, it probably isn't CL.
Here's Double Star's web site...
http://www.star15.com/rifles.html