IIRC, Data East also made optical rotary sticks with barrel-shaped yellow handles and the octagonal yellow and green handles are interchangeable.
The best way to be sure what kind of rotary stick you have is to look at the number of pins in the rotary circuit.
Opticals will have 4 pins -- power, ground, and 2 data lines.
Mechanicals will have 13 pins -- 12 directions and ground.
The reason for counting pins is that rotary encoders like the GP Wiz40 and KADE combine the 12 directions into 3 groups of 4 plus a ground = 4 wires.
You connect every third directional connection together -- 1(1), 2(2), 3(3), 4(1), 5(2), 6(3), 7(1), 8(2), 9(3), 10(1), 11(2), 12(3) + ground.
This only uses three inputs + ground, and the encoder sends the output when you change from one input to another.
Input 1->2, 2->3, or 3->1 = right turn.
Input 3->2, 2->1, or 1->3 = left turn.
Scott
P.S. Great pics, Tron84.
Mind if I use those two for the wiki? (assuming they are your pics

)
If they're not yours, do you remember where you got them?