Can non identical twins still be idnentical?

My friend has two twin girls, they are literally the splitting image of eachother! Although they had different placentas.

I said to my friend maybe she ovulated one egg that split into two, therefore they had the same dna that split into two just different placentas.

Or am I wrong??? I mean how can they NOT be indentical.. I can't even tell them apart! They are 8 months old.