Yes, it will dramatically lower the value of the instrument.
I honestly recommend against this kind of thing unless the original finish has ALREADY been destroyed by a bad home refinish job. However, if you are dead set on the Sir Paul look, I'd get a professional refin. I had a '55 P-bass recently restored and refinished by RSguitarworks. They did a terriffic job. I think they also repair finish Dings.
ps They are in Winchester, Kentucky!