We havent seen any maps yet. And its not likely, that they release them without showing the maps in several news. And there are no american skins for BotB.
So they might show the first map. And then maybe every week another until release.
But its not likely to post such a thing on facebook using morse-code. That was only used for the "big announcement". So it would be likely that it is something total unexpected, like an omaha map or a market garden map or whatever. I would rather expect market garden, as a lot of things are done, "just" maps are missing.