David is correct there are different length tubes and the Mark Mount Planer rests on the Way Tubes. Some do use the same posts such as the Band Saw and Strip Sander for example. As David said it is best that each SPT has it own posts otherwise you will have to align the tool each time the posts are switched and used.
Mark V completely upgraded to Mark 7
Mark V 520
All SPT's & 2 Power Stations
Model 10ER S/N R64000 first one I restored on bench w/ metal ends & retractable casters. Has Speed Changer, Model 4E Jointer, Jig Saw with lamp, a complete set of original accessories & much more.
Model 10E S/N 1077 oldest one I have restored. On bench w/ metal ends & retractable casters.