For the day postimage does a photo bucket:
Twisty has a dimple on the tailcap, rounded at the area where it meets the rubber button, SureFire printed on the face with the rubber boot for viewing best bezel down. The rubber boot is pretty much the same but does not stick out quite as far as a clicky.
Clicky does not have the dimple, has SureFire printed on the face best seen when light is laying down. At the rubber boot area there is a slight indention between the edge and boot the twisty does not have. And it has a near right angled edge at the top (calling the boot the top) instead of a rounded edge like the twisty.
At least that is what my 2 flat editions came with. I say 2 flats, they are the ones with flat sides 180 degrees apart from the clip versus the rounded flat areas some 270 degrees from the clip.