Yup, I saw it. The first time the investigator in question was using a light, I couldn't identify it, might have been a SL Scorpion like is usually used, but when she was back out looking at the red car, it was undeniably an L4.
The two most common lights I see on CSI (and CSI:Miami) are the SL Scorpion and the SF M4. Maybe they'll be replacing the Scorpions with L4's?
-Keith