That Clan ID was accurate. It is Clan ID #1 aka Beachhead Studios. It is one of the accounts they use to test ops/challenges. The ops/challenges that you see there are only 30 minute ops usually and if you were to look at them there were only one or two clans that participated. This clan actually gives us an idea of what they are testing and what we may expect to see in the future. As MWfan55 said, we can probably expect to see a Zombie challenge at some point in the future.
At this point, there is no way to enlist in these operations until they show up on the competitions page. The Beachhead clan is a special clan that I would not count as normal due to how they use it for testing and have a lot of ops/challenge badges for items that weren't open to the public to enlist in.