The only OEM factory door sill plates came on the Commemorative Edition SRT4s.
Neon SRT4 Door Sill Plates - JMB Performance and Powdercoat, LLC and a few other places still have aftermarket versions up on websites, not sure how good they are or even if they are still offered. I would assume it's a CAD pattern so I don't know why they wouldn't be able to just cut them out of stock aluminum or stainless.
NOW, did Mopar ever offer them as an OEM product you could buy and put on the car (like the stage packages), that I do not know. But they only came from the factory on the CEs.