Yes it is. ATI was originally the distributor for the gas piston kit when it first became available to the market. We stopped distributing it around the beginning of 2010 when Adams had grown enough to pick up their own distribution. We had a lot of inventory when that distribution agreement ended, so there's probably still a lot of ATI packaged ones floating around out there, all though if you open them and look, the block has the Adams name and symbol on it. When the distribution agreement ended, so did the warranty services, which were also then taken over by Adams. So, if you get one in an Adams box or an ATI box and need help w/ it or have issues, you can just go straight to the factory.
Hope that helps you out!