To use his celestial trait at 300, shouldn't there have been the star symbol on his base next to the 300 dial? I just noticed it wasn't printed on mine and thought maybe it was a defect on my own, but looking at the official previewed image from the heroclix website, it isn't on there either. The preview page describes it as trait to be used on all point levels. Just curious if this was an oversight or if there is a rule I'm missing/not understanding properly.

Asked the same question on the comments of the unit section and here's the replies I got:

But according to the rule book, page 18 "Trait abilities are indicated by a star symbol on a character’s base." So based on that, if it's not there, he doesn't have a trait and I couldn't find anything to say otherwise.

I can't be 100% sure on this one. Maybe we'll find out that Multi-Attack at 300 was an accident. But a * on the base has been left off on accident many times. It tells you "hey they have a trait" but it doesn't preclude the usage of a trait in it's absence. So even going with "dial over card" you DO NOT ignore the trait because the rule doesn't say "a character without a Trait symbol cannot use traits" or anything logically equivalent. Rather, as you quoted, it just lets you know that a Star is saying "Hey, I have a trait."

Also, if you check the Players guide it confirms the existence of a Trait for Dr Manhattan (the colossal) and yet there is no Trait STAR anywhere on any of its dials.

I would say it's an oversight and the intention was for Ziran to have the Celestial trait at 300. Even in the same set, Morg has a trait but lacks the star on his base.

There are several characters who have traits, but do not have the -symbol on their base. If the card has a trait, then the character has a trait. If this particular trait of Ziran's doesn't have a point cost with it, then it is active on his every dial.