Door Panel Help

[Ian71GMC]

I bought a driver's side door that didn't have an interior panel on it, but I already had one so it wasn't a big deal. But after getting the door mounted and the panel ready to put on, I discovered the little plastic pieces that are in the door to screw the panel into are gone. I've looked around, but no one sells the little pieces themselves. What can I buy that will do the job and hold my panels in place? Any help is appreciated!