I'm currently on leave and was thinking about taking my M961 back to Afghanistan with me. I'm a armed civilian contractor, not military and do not intend to mount the light to my rifle. Should I expect any issues while trying to get back home after my gig is up?

You can ask in the deployment section to get people much better versed than I am but depending on how you get there you may have troubles. We (same thing; armed civvy) fly commercial through Dubai. If it has a rail attachment on it it's a weapon accessory and subject to seizure in Dubai. I watched a guy get pulled out of line in front me and they dumped his bag out, there were 3 flashlights, 2 with rail clamps and they seized them.

ITAR: I don't think there is any ITAR consideration. The only thing that could make it one that I know of (not an ITAR expert) is if it were IR/NV related (in terms of lighting).

That light just takes drop-in batts right? Take the batts out and mail it to yourself. The post office has no problems with a light, but they don't like Li-ion batteries.