I am changing the doorknob on my front door.
I have a used doorknob that I bought at a rumage sale. I noticed it
has a small white dot near the edge. I'm assuming this dot is supposed
to be placed at the top, so that the knob user knows whether the
doorknob is locked or unlocked. Or maybe whether the door is open or
closed (I'm not sure, because there were no instructions).

The problem is that no matter which way I put the parts together in
the door, this dot can not be placed at the top. It's either a little
right of the top of the knob, or a little left of the bottom of the
knob. How can I fix this?