Colt Custom Cobras (Custom King Cobras)

I just purchased a set of Bright Stainless Custom Cobras, 4 inch and 6 inch. Does anyone have any information on these like how many were made? Or who they were made for? Lew Horton maybe? I have searched the web and some have said 500 sets were made and someone else said 250 sets. I have found four or five different pictures of them, all serial numbers under 200 including mine. Any info at all would be greatly appreciated, Thanks.