I think correct name for them is cage nuts. used in the computer industry. try googling them if nothing comes from here.
Being used on a Spider 58 years ago, I didn't realize it's such a common item for computers now. D'oh. Figured it was a 5mm unique part to furrrin' cars. Found four for sale in Italy for about $4 a piece...with $55 shipping! Since we have about 400 computers at work and engineers who save everything, I guess I'll try there. Good chance they are metric too. Thanks for the help, beats one raised eyebrow at the hardware store.