It's probably real, but we also don't know the full context. It could be a banter-y way of him introducing Facebook to a friend who hadn't heard of it, or something, and he could've just been kidding about actually giving information. Who knows for sure?
But knowing everything we know about Facebook now, it's probably more than likely true.
The EC did the merger evaluation with the assumption that they could.
In 2016 FB announced they were linking accounts in a ToS update.
It is not that they could or could not do it, but that they knew they could, but chose to hide that fact.