I agree the shape certainly looks Core Craft-ish but also believe all the CCs I've ever seen have the elongated diamond shape molded into the sides so I too am uncertain. No doubt designs changed over the decades. Here is an excerpt I found online concerning their all-fiberglass build...
By the early 1960's, labor costs prices the hand-laminated core boats out of the market. At this same time, the company had started building all fiberglass canoes, a fiberglass snow scoop, (called the Snow-Wonder) and built fiberglass snowmobile hoods for Arctic Cat. The canoes were shipped throughout the USA and some foreign countries.
If it is plastic then ?? Maybe a Dolphin as Yellowcanoe suggested?
I have yet to do a search for Core Craft or Dolphin on this forum but imgine there is good info in doing so that would help us out.
Anyone else out there have ideas as I certainly am no authority on canoe identification.
Thanks
Micah