A lot of electrical stuff which isn't allowed in new installations will still pass inspection in an existing property. Otherwise everybody would need to be rewiring their houses every time electric code changes. No (reasonable) inspector is going to make you swap all your outlets just because they're upside down. But if you are an electrician wiring new outlets then you would have to put them in the corect way.

Another big example of this is ungrounded outlets. You definitely aren't allowed to used ungrounded wire for any new instalation but if you own a house where ungrounded wire is being used then in most cases an inspector will not make you replace it as long as all the recepticals on it are swapped over to GFI outlets and none of them are in a kitchen or bathroom.