Take a look here (Click to enlarge):
I strongly recommend removing the LASER assembly while cleaning! S&W will give you another impossibly small Allen wrench if asked, but hang on to the one you have!
Check both sides for proper activation of the LASER. Put some light Break Free or gun oil on the lens to help when cleaning time comes. DO NOT use solvent on the lens in the dust cover! I recommend a cotton swab with some window cleaner.
Don't get me wrong, I like the gun but dumping solvent into this assembly will not turn out well!