Why is the laser/illuminator tied down with wire like that? Don't they have picatinny mounts machined into the housing?

Dummy-corded down to prevent loss in case the mount comes loose, I suspect.

Helicopter seems to be CH-46E BuNo 153402 modex YS-02, currently preserved in North Carolina (half) in its former HMM-162 markings, although they differ from the ones in the picture.

Gear includes M16A4 with AN/PVQ-31 (presumably -31A, Trijicon TA31RCO-A4CP, with BDC for a 20" barrel) telescopic sight with TA91 anti-reflection device, Grip Pod, KAC rail cover, Eagle SPC, Surefire HL1 helmet light, and other stuff I'm either unable to or too lazy to identify.