OK I'm flushing my coolant and I see the stat has a small hole in the flange already that looks factory made with a tiny bracket thing on the underside and a tiny ball inside. I'm assuming this is an air bleed so I don't need to drill a hole correct?

I believe that to be the intent of it, but have found it'* a toss up on whether it will work as designed. I put a 1/16th hole in regardless.

I'd drill one anyway, I'd even vote for two.