I have never had walnut go lighter over time (doesn't mean it can't happen). KK; my guess would be that the under side of the stock is the true color and the top has aged in some way - I would strongly suspect oxygen but it could be any active atmospheric agent. DF; I have soaked stocks in acetone for days, I think that the finish after soaknig is almost non-existant, but if you remove that fine "crust" lighter colored wood is exposed. My observations are the same as yours in a year or two the colours again match up. --- John Can.
