Just bought 100 of them on Ebay for $12. It's a standard riv-nut available in any thread you'd like to install. There are special tools to install them but you don't need them. Look on You Tube for a simple way to install them with commonly available hardware.
sf1954 is correct on the item in the second picture. It's a "well nut" or sometimes called a "expansion nut" with the rubber torn off. Used all over under the hood and along the side rails of a soft top mounting points. I buy replacements at ACE Hardware, cheaper than the HMMWV sources and looks identical. Not sure what the first picture is of, looks like a riv-nut.
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