Either procedure is fine. It is possible to pre-glass all Buffalo Boat side panels in advance, both sides, while the panels are flat on a table. It's easier to do good work that way. The Buffalo Boat side panels do not have a great deal of bend so you can pre-glass both sides and then still bend them onto the boat. Then you rely on fiberglass tape to overlap the seams. But you don't have to do it that way. Stitch and glue is a flexible way to build. You can proceed with any sequence of events that makes sense to you.
For the bottom panel I recommend pre-glassing the outside surface flat on a table. Then bend it onto the form with the inside still not glassed. Then glass the inside after removing the temporary rib-like formers. But do remember to straighten the hull, usually with a transtom corner to transom corner winch line, before glassing.....