Need Basic Help

OK folks. I think I got the nerve-up to try some things I've been wanting to do. Does any have a picture of a basic LED emitter that indicates which end is positive and which side is negative? I know these are not the correct terms (forgot the real names), but I think you know what I'm asking. In its simplist form, I want to know where to solder the red and black wires to the emitter.

Positive end of the emitter has a rectangular slot cut out from one the short legs

Got it, thanks. Next question... when security the emitter to the heatsink, do I use Artic Silver Thermal Adhesive or Artic Silver Thermal Compound?

Depends,
If the LS is not red, you can use either one. The thermal adhesive is permanent epoxy, the thermal compound is not a glue so it does not "stick". Thermal compound is what they use between heatsinks and heat producing solid state devices such as power transistors, computer CPUs and now, high output LEDs.
If you are using a Luxeon Star and use screws to hold it down against the heatsink, thermal compound is better. If just using the emitter, you must use epoxy so it will stay in place and not fall off.
Generally speaking, epoxy is forever and compound is for swapping heatsinks and LEDs. Hope that helps

Thank you. SureFire must have used the compound in the KL1, since the only thing really holding the emitter to the heat-sink was the solder joints of each contact.