I am unaware of a term for a memory that the rememberer is uncertain is genuine or not. The term false memories is used to represent memories that are not real (as it were). Wikipedia has an informative page on false memory syndrome, a "condition in which a person's identity and relationships are affected by memories which are factually incorrect but are strongly believed." The page also lists other types of memories of uncertain origin including planted memories and indoctrinated memories.
Hyperreality describes "an inability of consciousness to distinguish reality from a simulation of reality". Using this definition, the OP's uncertain memories could perhaps be called hyperreal memories.
Neuroscientists believe that memories are not stored and tagged as genuine or dream. In fact, it is suggested that memories are not stored discretely as, one might imagine, something akin to files. Instead, they are stored as interconnected chains of separate data with no differentiator for something that occurred in reality against something that was dreamt. In other words, dreams are stored just as experienced realities.