Shelby America - Slotted Mags

[Crazyone]

So my Dad is coming up from Arizona this week and is bringing a set of slotted mags for my Bronco that he has had stored for about 20 years. He said he pulled them out and was cleaning them up and noticed that on the back of the wheels is cast in "Shelby America" Anybody know anything about these? Just curious more than anything. Seems like anything Shelby is hard to come by and big $$$$.

[Viperwolf1]

Shelby Cal 500's. Nothing special really. I have a set.