Composites have a lot of variation so "Fiberglass" usually is taken to mean glass fibers embedded in styrene plastic. Sometimes epoxy is used as the matrix and of course other fibers are used. It amounts to important differences for the end user.
Styrene is stiffer than epoxy. Kevlar and carbon fiber give a stiffer layups than glass.

Composites although very strong are unfortunately flexible, so builders commonly use thicker material to compensate for the flexibility of "fiberglass". An option to increased thickness is the inclusion of stiffening ridges, compound curves in surfaces and foam core panels.

Steel structures are thin for lightness(and economy) and are stamped into compound curves and reinforced in other ways to produce a rigid stable shape.

The best shape for a steel structure may not be the best shape for a composite structure, so do not expect them to be the same.

I like working with composite bodies as changes are so easily made, but do not expose them to a lot of heat and stress as they can change shape.

My front renders are fiberglass. I bought them years ago I think from Peter Z. back in the Midwest. I didn't weigh them before I put them on so I can't tell you the weight difference on mine.
I rattle can sprayed them flat black. With a wet sand and buff, they came out looking nice. I like that flat black front end look.

Weight is the key 38lbs sounds pretty good, rust free for life, skipping breakfast I dont think so, Hunger makes a worse enemy than weight.

38 lbs is a lot for a body panel. The stock hood weighs only 30 lbs.

Yep a combined weight saving of all the items mentioned is not a bad thing for those looking for that little advantage in racing. For street steel is the deal and lucky 1200 people are spoilt for choice.