I'm righty, play righty, though I know several lefties that play righty. In fact, the vast majority of the lefties I know that play guitar do play righty. In a lopsided ratio, they are by far some of the better players around. The few lefties that I do know that play symmetrically correct left handed instruments, I have to believe it is out of stubborn insistence; shortage of left-handed instruments, etc. Even a lefty playing a righty string orientation upside down, Albert King, Dick Dale, Doyle II, makes more sense because, like most, we first learn to play on someone else's right handed instrument.
As it's been stated before, the experts in charge of this kind of research are beginning to believe there is no such thing as a left-handed person; righties and ambidextrous righties with a ambidextrous dominant leaning with some things. For example, many lefties perform some tasks as a righty, and many lefties with a dominant hand injury adapt to righty ways easier than their counterparts.
As a righty who began playing before he had a computer with a mouse, my first mouse, I used lefty. I also put my wallet in my left hind pocket like a lefty. It may be because of fret work and drive thru fast food proclivity, but doing things out the driver's side window with the left hand like a drive up ATM are no trouble. That may not seem a big deal, but ever notice at an ATM how many people have to partially open a door, swing their right side around just to use their right hand?
Lastly, in my late teens, I broke a few fingers on my left hand. They were actually smashed and shattered. Not thinking they would ever be the same, I tried learning lefty. Couldn't do it. The fretting part was actually easy, but after the fingers healed, I could never get the plectrum portion down.