Bolt-on Center caps?

Aformentioned Center caps

What are these?! I want some on my car, but i dont know if they'd fit, or for that matter, where i'd find a 4th one Lol.. Any of you guys seen these before? I didnt have the slightest clue they even exsisted.

EDIT: Found an ad that actually said what car it came off of,

http://files.conceptcarz.com/img/Hon...9-PVGP-002.jpg

Now, i wonder if they'll fit?

http://www.ebay.com/itm/1979-80-81-1...-/390204103485

http://www.ebay.com/itm/1979-1980-HO...-/310368793712

Those are even more oldschool than the ones i saw.. I think they fit, the bolt pattern seems to be 4x100 for those 'ludes, too, but i have to check the diamiter of my inner wheel..

http://www.ebay.com/itm/1979-80-81-1...m=310018222807
This ad lists the size of the caps

I'm looking at my rims in my sig and wonder if I could have used those on my car. :(