Both work well except the 3M model's meter bar does not work (as most of this model do not) so the bar has been removed to avoid the need to lift up each time you use it.
Konica 1 w/50mm f3.5 lens and case. Lens collapses into face of body. $85.00
Konica 3m w/50mm F1.8 lens and case Bright viewfinder and rangefinder works well. $125
IIRC the IIIm has a provision for shooting half frame, vertical format images. It would be good if Drew B states whether that device is included.
I have a Konica IIIa with the f1.8 lens. It is a wonderful camera, excellent viewfinder.
Never noticed it before, but I will check and see. Ok, there isn't any device inside to lesson the frame size but the winder has to be wound twice for full size 35mm film