With a female mold, the outermost layer goes on first. Before applying gelcoat to the mold many hours were spent preparing the surface. If you take the trouble to carefully fair and polish the mold’s working surface, your boat emerges from the mold with a shiny exterior finish already in place.
The fabric is laid out in the mold’s interior before being wet out. Then multiple layers of fabric are built up into a laminate, and after the resin in all the layers has set up hard and cured, the now solid part can be separated from the mold. For this to be possible, the mold’s working surface must first be coated with a waxy separating agent before the laminating begins.
Here is a close up of the hull side showing the layers of laminate.