I did some research on the East Coast based Fleetcraft boats after redoing a 1957 Fleetcraft Imperial that has been in my family since my uncle bought it new in Michigan in 1957. As has been noted here, another Fleet Craft company was based in California, producing larger hulls than what i found for the East coast Fleetcraft boats. I obtained some early sales brochures from a man in NJ who had bought a plywood Fleetcraft in 1954, and apparently the company was just getting into fiberglass hulls about then. I also called the owner/designer of Fleetcraft boats in 1996 or so. His name was Mel Bukowsky, and he was happy to spend a few minutes discussing the boats with me.
Being based in NJ, he knew his customers would be using the boats in the ocean, so he designed the bows to be very buoyant, so they would ride over bigger waves, and so that the passengers could ride up front where it was drier. He also designed the transom and stern to efficiently plane use smaller motors, like the commonly used 25 to 30 HP motors of the time. He was not pleased to hear I was using a '59 Evinrude 50 on mine, and truthfully it is a lot of weight for that narrow stern and low transom. He was very pleased that I was still using one of his Imperials and said they were the top of the line in the late 50's. I recently learned that he passed away in 2012 at age 81.
Two of the sales brochures are from about the mid 50's, but are not dated. the earlier one is probably 1954, since it described the boat the NJ fellow had. The second is about 1956 and has a 14' hull called the Holiday that would become the Fleetcraft Imperial in 1957. It has a lot of the same Philippine mahogany wood trim, but lacks the distinctive fins and the fancy upholstery and rear deck. I am not sure how long the fins and the single layer fibereglass hulls were sold, but someone on Fiberglassics has one that may be from 1959.
The last brochure is from 1967, and I am not sure if it is the same company, since the hulls are much larger and have a double bottom, and the Fleet Craft name is spelled in two words instead of one. This is the Company associated with the Flotilla Corporation in Woodbine NJ. The earlier years brochures are still in the NJ area, one in Philadelphia PA, and one in Palmyra NJ. It could be that Flotilla bought the earlier company, but I cannot say.
Attached is a picture of my 57 Imperial, and there are a couple of other shots in the projects section. the sales brochures are attached as pdf's and since they are scans of copies are not perfect, but may be a good resource for others.