I bought a set of rears for my'40 from a place in Oregon. They didn't even come close to fitting correctly. To their credit, they took them back and gave a full refund. Quite a few on this board have recommended R&R Fibreglass. In the end, I was able to find a pair of used steel fenders that didn't need too much work.
At the end of the day, unless you are trying for a totally stock truck, I think good quality glass fenders are fine - many trucks and cars out there with glass parts.
