I have found this type of fastener on both the rear fenders, and again on the spare tire carrier on my 56 3600. Can anybody tell me what it is called, and what tool is used with it?

[img]http://dougherbert.org/eve/20100108%20Spare%20Tire%20Fastener/DSC_1867.JPG.preview.jpg[/img]

Thanks,
Doug