I think they must be new models as I too have not heard of the SL range being modified to carry LED's! Anyone else no anything about this new modification?
Unless they messed around with the graphics or they were just prototypes it looks like the rechargable has a smooth reflector and the alkaline version has a textured reflector.
I talked to a Streamlight Rep about these at the La. Chiefs' Of Police convention a month or so ago. He said that one of the big agencies in Texas had requested the SL version, and that they were going to be out sometime before the end of the year.