That outlet might have been "harvested" from an earlier project that some electrician had, where they removed the bridge so they could make an outlet that was live on top and switched on bottom. This is a surprise but there's nothing wrong with it as long as the screws are tight.
As for the 12 ga coming out, this is a bad idea that will probably result in no problem at all. Wire gauge signals current capability to the electrician, and if he sees 12 he's likely to think he can load it up more than is right.
I did some overseas work where I discovered that you are not allowed to use oversize wire out of a breaker -- the wire size TELLS the electrician what the breaker rating is.
A good answer is easier with a clear question giving the make and model of everything. "The biggest problem in communication is the illusion that it has taken place." -- G. “Bernie” Shaw
