Sorry, I forgot to answer your question. Gel-coat just means there is a coat (or sometimes two coats) of resin brushed into the molds, that is then backed with fiberglass cloth/resin for strength. The gauntlets in the pics have a single layer of gel-coat and fiberglassed backed.
Resin "only", would mean a thick coat of some type of casting resin with no fiberglass backing. It isn't as durable as fiberglass backed gel-coat.
Hope that answers your question.