Definitely were built and flown. From Wikipedia:
Burgess-Dunne The Burgess Company and Curtiss, based in Marblehead, Mass, USA gained the US manufacturing rights and built a series of aircraft based on the D.8. They became known as Burgess-Dunne machines and were mostly single-float planes. The first flew in March 1914,[13] piloted by Clifford Webster. Apart from wingtip floats the wings were identical to those of the D8, but the fuselage was revised with a distinct nacelle containing a more enclosed cockpit. The aircraft was a single-seater, with the heavier 100 hp (75 kW) Curtiss OXX2 water-cooled engine moved forwards, shortening the fuselage and with its radiator placed between engine and pilot. The single float was 17 ft 8 in (5.38 m) long, shallow and flat bottomed viewed from in front, with a single step. The prototype behaved well in the air and on the water.[14] The second machine was very similar to the first, but room was made for a second seat by replacing the single fuselage mounted radiator with a pair fixed to the rear float struts.[13]
The second machine was bought by the Canadian government for the Canadian Aviation Corps and was their first military aircraft. It was shipped to Europe for service in World War I, but was seriously damaged in transit and not used. The third machine, another two-seater but powered[15] by a Salmson M-9 radial providing 135 hp (101 kW), was delivered to the US Signal Corps in either 1914 or 1915.[16] Two were also delivered to the US Navy[17] as type AH-7, fitted with a 90 hp (67 kW) Curtiss engine[15] and AH-10 with the 100 hp Curtiss. The latter set a US altitude record of 10,000 fft (3,050 m) on 23 April 1915.[15] One Burgess-Dunne was configured as a landplane for a time.[18][19]
The Burgess-Dunne types were[20]
BDI - as the prototype.
BD - as the second aircraft, first aimed at the military market then as a sports plane.[15]
BDH - a two-seater with a 140 hp (100 kW) Sturtevant V-8 engine[15] and a slightly increased span (46 ft; 14 m).
BDF - a three-seat, flying boat variant with the Curtiss engine but a span increased to 53 ft (16 m).
That explains a lot about this aircraft! Thanks for posting this info!
Craig