Wow, neat.
Thanks for the info, Bruce. I would have liked it as a mod, but I like it even more as a factor variation. Since you have 8 P1s and only 3 of these, I prefer to think of it as almost 3 times rarer than a P1.
I think it's ok to use the phrase "dot display" for the P2/P3 displays, since the display segments are actually little disks. "Dot matrix" is clearly wrong since they are not arranged in a matrix unless you are talking about modern OLED watches (Fossil, APUS etc). For the 70s Hughes displays, "dot segment" seems more correct since the display elements are little rounded rectangles rather than little round dots.
People tend to glom onto whatever term they are used to hearing and since "dot matrix" has become part of the vernacular, it will continue to be misapplied. Good luck stamping it out. People can't even keep "LED" and "LCD" straight even though they look totally different.
-abe.