The lasers will be one more tool in the kit. The weakness of the AC-130 platform is MANPADS. As far back as the Gulf War we were losing gunships to shoulder-fired SAMS. The task has been to give the AC-130 the ability to stand further away from the target, beyond the slant range of the portable stuff. Lasers will help with that. I’m guessing the 105 will be deleted when that happens (but that’s just a guess).
C-17s have had an anti-MANPADS system for more than a decade. They were pointed out to me on a C-17 in 2005. Small lasers that burned out / degraded the seeker head. I’m sure this thing is loaded with them.
Here:
http://www.globalsecurity.org/military/systems/aircraft/systems/laircm.htm