Those TIR optics with the concentric ring features are not Fresnel lenses. They are all TIR optics - just different designs.
A Fresnel lens requires less lens material required compared to a conventional spherical lens. It does this by breaking the lens into a set of concentric annular sections known as Fresnel zones. The concentric ring features of some SureFire TIR optics do not appear to be Fresnel zones and the optic itself is still as thick as other TIR optics.
It appears to me that the function of the concentric ring features are a means of spreading the beam out rather than concentrating it further which I would expect Fresnel zones to do.
Sorry for such a long delay but I have been deployed and just returned. I will try to get some beam shots soon. If anyone has any good info on how to take them please let me know. Also, I am thinking of selling one of the DEF 1 and maybe a DEF3 if anyone is interested. Thanks!