I'm not sure what you mean by the "lip". I've heard that there were a few different companies that made the slots, so if there is a difference in the lips that may be why. Here is the best picture I have of the front.
Sorry man, you'll have a hard time prying those slots away from me! I like the look a lot on my truck, and have a pretty good amount of money invested in tires, polishing, and lug nuts to get them to work on my truck.
My wheels aren't 16x10s, they are 16.5x9.75 just like the other ones that you've found. You'll have a hard time finding 16x10s since to my knowledge no one ever made these style of wheels in a 16". The only size I've ever seen with the 8-bolt pattern is 16.5s.
My wheels were made by Superior Industries in Van Nuys, Ca and are called a "SuperDrag I". I don't think this company is in business anymore, and to my knowledge there hasn't been any company producing this type of wheel in an 8-bolt pattern for at least 20 years. I think it would be awesome for a company to reproduce this wheel in modern sizes, but I'm not holding my breath.