talk about a blast from the past. in the late 70's and early 80's I worked for "Off Road Supermarket" which was the retail side of "Off Road Marketing". I installed thousand's of those part time kits and taught many mechanics how to install them.
I knew both Vanzant brothers as well as their siblings. yes "Off Road Marketing" invented the kit and it was stolen by many companies including "Mile Marker". it's the main reason I still have a bad taste in my mouth for Mile Marker. the part time kit wasn't their only invention, they also had Bug Off's which was a bug screen for the front of Jeeps, they also had the rear bumper tire carrier for S-10 blazers, they also did the Wolverine conversions which converted 2wd Toyota Pickups to 4wd however that ended in 1979 when Toyota started selling 4x4 pick up's here.
I would leave it part time if it was mine. however if you are bound and determined to go back to stock, you need to remove parts 182(x2) and 180. you must source part 124 this is a needle bearing retainer and must be in place. after you install everything you must check the end play of the rear out put shaft. if I remember correctly the end play is .010-.030. the end play is set with shims between the rear output yoke and the rear bearing. the pics you posted don't show the shims, bearing, or yoke. if you need any advice ask away.
highdesertranger