Is the plane a kit or an ARF? It's been a while since I've seen an ARF done bad enough to be that dramtically out of trim. However, it is possible, esp if you did the hinging and control linkage set up yourself, and don't have expereince doing it.

Even if you're going to fly it, it could pay to get another set of eyeballs to check over the plane and make sure everything is good.