I'm not even sure it's a "wannabe" page, the only commonality is the name "Ahlmans", and it's not like that's a unique name.
It won't hurt to let the real Ahlmans know, but considering that it doesn't appear that they are expressly trying to mimic the real Ahlmans, I doubt Facebook cares and I doubt the real Ahlmans will be able to do anything about it.