yes - it's very common in fiberglassing to save time by stretching fabric (such as fleece or grille cloth) over a frame of wood to build an initial shape. That fabric is impregnated with resin, and left to cure. Once cured, this shape serves as the mold if you will for the real part that is made of fiberglass fabric (cloth, chop mat, roving weave, knytex, etc...)

Assume that the original "stretch" of every-day fabric adds no strength to your part....