So far I've found photos of 3 versions that were licensed by the  Connecticut DMV. There is a 2613T, a U104U and a A3175P (which is the one given to the NASM). I  would hazard a guess that the T is the older version, followed by the U and then the P just because the number 2613T is sequentially lower than U104U. I've written to the Conn DMV to see if there is any other info on file.

According to Aerofiles (scroll down to Fulton), there were 3  FAA approved prototypes - NX60374, NX61037and  N74104. According to NSAM there was a N74153, certified in December 1950 and a N74154, certified in June 1953. So the records of what was produced when are not yet complete.

Another interesting fact from Aerofiles (scroll down to GA-2 Duck) is that four sets of fabric covered wings from the GA-2 Duck, manufactured as dealer demonstrators, were sold for use on the 1947 Fulton AIRPHIBIAN prototype. The Duck wingspan was 36'0" and the N74154 wing span was 36'6". The Duck also used a 145 hp Franklin 6A4 as a pusher engine and the N74 used the same engine as a puller. Whereas the later AIRPHIBIANS were modifications of the STINSON voyager 185.

They are very different, hopefully my dad will give me some reasons behind the differences. I'll refer to them as the T, the U and the A.

(That is Wayne's hand in the T photo and he is also driving the U in the bottom picture. We are trying to find out the name of the woman in the color picture of the T).

- The wheels. The U's wheel cowling and lead in to the body and the body attachment are radically different from the T's. The U is much more aerodynamic. I think the U even looks lower. It seems as if the angle of the wheel to body is different. There are also running lights in the wheel cowling of the U and not in the T.

- The air intakes are also different. I blew up the photos and saw that the top openings of the U are quite square with rounded corners. The openings of the T are much more rounded on the outside top corners. It also seems that the U's bottom opening is narrower than the T's.

	N74104
These are the only photos that I found of N numbers. N74154 (license plate A3175P, which was given to the NASM) and the N74104, which looks like it goes with license plate U104U.
GA-2 Duck	Stinson Voyager 185	AIRPHIBIAN Cutaway Drawing