The ONLY time an '82 or '83 uses an FA69/2 is the for the front vented rotors on the Aspencade models. Some Aspencades (only some '82's) may have had a rear vented rotor, and that one will be an FA69/2 as well.
If the only difference between the three pads is their thickness (10mm, 9mm, 11.3mm) then I don't see what the real difference is. The brake calipers can be opened wide enough that the widest will fit, and the two widest will wear down to the thickness of the narrowest soon enough. I've always used the 69's on my 83 Aspy and they've worked great - front and rear.