The Buck "Frontiersman" was a version of the "Nemo" dive knife and was released at about the same time. I remember the knives being advertised in "Skin Diver" magazine in the sixties.
As for a Bowie my idea was pretty much based on the "Iron Mistress" in the old B&W movie with Alan Ladd and the knives subsequently reused for the later Jim Bowie TV series. At the time I got my Dad to make a knife based on my sketches on watching the TV show, no video recorders in those days so it had to be done from memory and watching more of the TV episodes. The resultant knife is now over 50 years old and was built to be super strong with a screw-on long cylinder nut retaining the bronze handle butt and bronze cross guard specially cast at a local foundry and hand finished by myself with files and post shaping on a buffing wheel. Originally it had a gleaming mirror finish blade and the bronze fittings all shone like gold, but over time the bronze etched with sweat from my hands and the leather washer handle was smoothed down with wear. A great blade to swing and chop with. The tang under the leather handle is quite thick and the leather washers barely cover it, so it is not a skinny tang like you see on some blades of the type. The blade is 2" wide and about .22" thick as surface grinding took it down from the original bar stock of 0.25". The steel runs from end to end at that thickness until it is threaded for the cylinder nut, an idea that I picked up from a smaller stag handled Bowie with aluminium bronze fittings.