The early arch hunters were made with stainless. Look at early 1990's. They switched to fiberglass around 1998. That didn't work out so well so they switched back to stainless by 2000.
Want to see a really interesting fiberglass arch design, take a look at irwins, I think 43. that had an arch at the back on a center cockpit. Looked like the old dodge nascar superbee.