The higher the quality of gun usually predicts the quality of the wood. A stocker will pick out a stock blank and try to match the for-end wood to it, especially on the higher graded guns. In the case of the pigeon grade it was basically a fancier NO. 3 gun.
According to Wayne, the serial numbers match on the stock. No one will know if it was ever sent back to the factory for a replacement stock, but seeing as the serial numbers do match is good enough.