What is the antique value of Danial Boone 1930 20 gauge E6216 double barrell shotgun?

Without seeing it, I would guess that the antique value is nonexistant. The name "Danial Boone" is unrelated to the American frontiersman and is only there to sell the shotgun. It is possible that the gun is American manufacture (Crescent City made thousands of inexpensive shotguns with every name brand you could imagine) or it could be a Spanish or Belgian shotgun. In any case, it is not a Purdy or Winchester or other brand which would command "antique" value. If the gun functions, it would be considered a field piece and could be worth a few hundred dollars. If it is worn out, it is a wall hanger and would not be worth the cost of restoration.