They are held on by melted plastic.
I was pulling on one of them thinking it snapped in, but it didn't.
What I did while panel was off was get a small nail hold it with vise grips heat it till glowing push into the melted plastic stud (but not to far might go through front) and pull then do the others and it shold come off.
I managed to remove the grills by cutting away the melted part of the stud. I'll keep in mind your suggestions for next time. I was almost tempted to see if my soldering gun would soften the plastic enough to pull the stud free.
To reattach it you can use either jb weld or equalivilant or melt some plastic back onto the stud push through the hole and heat a bolt up and push onto the stud to flatten it out so it stays.