Even if you put it up there backwards, it LOOKS like the teeth are engaged, but, not Fully, so, put it on, look at it carefully.
Remove, flip it over, put it on.
Look at how the teeth engage.

There Could be some mark, or, lay it on the table, look at the gear, is the center of it high?
Might be able to decide that way, If you knew more about Why the teeth are not lined up either way the gear is installed.

Just do it both ways and look at the difference.