2003 BuickRegal LS. The rocker panel has two different clip styles. One fits into round holed stamped into th rocker panel the other clip snaps into rectangular holes. I need to find out what that clip is.

Hello, I'd have to advise you to reach out to your local GM vehicle dealership to consult with their parts department about this. It's beyond the scope of anyone here for sure. As always you can reach out to a shop near you who can help too. https://repairpal.com/auto-repair-near-me Click the link or call us at 877-913-1554. We'll gladly find you a certified RepairPal shop in your area.