I see parts from more than two Model 10's there on the workbench. The two headstocks is see include the last version (7) and an earlier version with the double wedge locks. The long and the short of it show up with the two base castings. Something I have found helpful having more than one dissembled Model 10 at a time is to keep their parts, except the way tubes which I mark, in separate bins. I currently have three in bins. As I have found there are 1 to 7 different versions of the parts. All are interchangeable individually or as an assembly. You could end up with that elusive Model 10Er instead of a 10E or 10ER.
Be careful so you don't end up with something like this.
The extension table in the upper right corner (background) is a metal one mounted on a wood bracket and tailstock. The one in the lower left (foreground) is a wood extension table mounted on a metal bracket and tailstock.
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.