The problem is that many American companies had different names for the same thing. In general, the first two are Barlows, extra long bolster, both blades at one end, generally smooth handle getting wider from the bolster and terminating in to a round butt.
The knife on the right is certainly a jackknife (blades at the same end) but has a standard short bolster, and an asymmetrical handle.
Overall it comes down to what it was marketed as. Once could say the blade is more sodbuster than spey ( it is meant to spey but what we call spey these days has a bit of a flat clip point to it).