<<I'm surprised if there's not an original option for the 'Bright Wheel Lip Mouldings' by themselves..... >>
Nope, there wasn't - if you wanted wheel lip moldings, you had to order the Z21 Style Trim package and take all of it - drip moldings, quarter louvers, wheel opening moldings, taillight dividers, headlamp bezel trim, etc.
The original owner of my X33 car ordered it with just about everything you could get on a Z/28, but didn't like the Camaro emblem on the fender or the quarter louvers, so he removed them, brazed the holes shut, and painted it between the wheel openings from the feature line down. Different folks, different strokes.