Aren't door knobs supposed to be on the right hand side of entry doors?

In real life door knobs can be left or right. It depends on the layout of the house and the direction in which the door is supposed to open.

I sims you can rotate doors by pressing < and > while placing them. (on my azerty keyboard this is, and ; ) For doors that look the same on both sides, this works very well. For doors with a different appearance on both sides, for example some of the realm of magic doors, flipping them makes less sense.