The I wish that I could print the some of the drawings that I have to show the progressive changes in the configuration of the 367-80 to the 717 and the 717 to the production version of the 707.
That was my point - the 367-80 was developed
into the 707 via the changes you describe.
That's rather different from the original assertion that the Dash 80
was the 707 - it wasn't, at least not the 707 as we have come to know it.