Wheel locks...no key. Any ideas..?

So got these old school slots on my car....and they have a round "collar" lock on one lug-nut. One on each rear wheel (2 total). Prev owner didnt give me a key for them! Of course I didnt notice before leaving with the car...

Any ideas how to get them off...or anyone recognize the brand and know where to get a key...? You can spin them with your fingers round/round...but obviously they dont thread off/on...so I'm stumped.

Thanks guys! Check out the pic...