I was a licensed electrician (Actually EE) Automation Engineer, plant safety, and fire marshal for a 3.8 million sq ft manufacturing and research facility (before 1st retirement) and I always preferred the ground pin up orientation, more because it is longer than the others and easier to see when this pin is up, because it has to be put in first. As the plug comes out of the outlet, it is also the last pin out. This longer pin is to ground the appliance, tool, or whatever before power is applied to it, and to keep it grounded until after the power is removed when the power pins are exiting the receptacle. Kind of a neat idea once you understand why it's longer.
In the USA, there has never been anything requiring the plugs and outlets to be oriented either way, but "The authority Having Jurisdiction", meaning any local inspector, can require it to be the way that he likes best and can fail you if you don't follow "his" rules. Fortunately, most areas of the country adopt the National Electrical Code, which is part of The National Fire Code, and follow that for compliance. Get into the big cities or certain industries, and all bets are off as to what is followed. Some places basically follow the NFPA National Electric Code, and then add to it their own local code. It's best to find out what is required by contacting a local government office and asking. If there is a local inspector or department, that's where you find out what the local requirements are. Most inspectors are friendly and easy to deal with, if you don't try to ruin their day. Cooperate with them and all will be fine. They will tell you what to follow, and even provide help before you buy anything, so no re-wiring is required. In most places, a homeowner is permitted to do their own wiring, if they follow the code requirements. Sometimes a local quiz is required to be certain that you know what you are doing. The inspector will tell you what you need.
BTW, the Sawmillcreek.com forum has the entire 2014 National Electrical Code available on their "Workshops" sub forum, if you should care to look anything up. I don't believe that a newer version is available yet, and purchasing a copy of the latest can be quite expensive anyway. When I need to look something up now, I just go to sawmillcreek, now that I'm retired and nobody pays for a copy for me anymore.
I can see many things in the first photos in this old post, that would definitely fail a code inspection. Learn what is really required, for safety reasons, before doing this. Your life and the lives of your family upstairs might depend on this. Don't take chances when dealing with electrical or fire safety.
Charley