What are these things called?

[CHolmes]

Anyone know where I can get those little square nuts that snap in the square holes on the body panels? I don't even know what the proper name of these things would be. Are they still available?

[Kent]

They're called "caged nuts." You can get them at many hardware stores, or at industrial supply stores like McMaster-Carr

[4xbill]

Try here http://www.abcorfasteners.com/ too