Good question. Gresham had the head of the LA chapter of the ACLU on a few weeks back, they are backing a pro-2A case. She also said the national ACLU was going to re-evaluate their position on the 2A, but ddon't hold your breath.
As for the ad, air time is air time, the ACLU or their agency may not have bought that specific time slot, but instead bought a package where it will run X times in prime time for $Y. I made the same comment about Progressive insurance which is anti 2a, hell, just about anti-everything that made this country great. It is called Progressive (in the same way bho and Hillery are Progressives) for a reason.
BTW, if you haven't already, please stop by the the Down Range Cafe and look for the New Members thread. Then tell us a bit about yourself and get a "proper" welcome in return.