The DA Aqua Master is a great diving regulator, but it is the most common double hose that was made.
The 3323 West Delhi Rd. address makes it a 1960 or 1961, which is not the most common, but other than that it is nothing special.
It has the short yoke (typical of the time) which is also less desirable for use with a banjo fitting SPG (pressure gauge) adaptor.
The hoses look in decent shape, but it is hard to tell from the pictures.
The chrome looks slightly below average in its condition.
All this being said it is still a great regulator with a lot of potential. Due to the condition of the chrome it is a good candidate to be totally re-chromed and converted into a Phoenix RAM or just rebuild and recondition for diving. In its condition (based on the pictures) it has little collectors value, but a lot of potential for a great diving regulator.
Price can vary a lot. I would say $50 is the low end, but if you put it in eBay under the right conditions (a feeding frenzy) it could bring $150. At this point with the present economy I would not count on the high end more likely closer to the lower end, but you never know.
In that condition, I personally would never pay more than about $75 for it (probably less), but I can be patient.
You could post it at VintageDoubleHose.com and get more opinions. You could even sell it over there.
Hope this helps
Good luck
Added:
BTW, if you get a reasonable offer from Jimmer or Slonda, at least you will know that it is going to a good home.
I am sure either one of them will restore or have it restored. And they will dive it as it was intended. IMHO, this regulator doesn’t really belong as a wall hanger.