Floor shift. Two places to hook shift linkage, one forward and one rear. My pic below shows how mine looks with 2 places to attach linkage. A normal 3 spd only has one place to hook up. Make sense?
Believe the top example shows the two connection spots I mentioned in my response. One for the shifter and one for the lock out steering column used on 71-73s
Codes your showing appear to just be the casting numbers from the main case not the application. The D2 does suggest the later style we're discussing
Here is a 70 4 speed examples - they used the locking steering column arrangement also
The center arm has to connection points one top, one bottom. The three rods (blue arrows) connect to the shifter. Lower one goes to the center arm on the trans \
The one lower connection rod (green arrow) attaches to the steering column lower end so that it can not be moved once the car is locked by removing
the ignition key