I think if you submitted the part you shouldn't be able to earn points on it whether you know what it is or not. Because if you submitted it oyu have an unfair advantage in knowing what sets you own, or what it came with in a parts lot, which gives you extra hints.
As to time zones, if you get up early and post it in the morning your time, then that will be when almost everyone on the forum is awake., or soon will be.