I bought a 1950s Ithaca 37 that had a slip on pad. Under the pad was significantly darker than the exposed wood. Like perfect line and substantially darker. Stripped the finish and redid the stock.
The solution is to put a Pachmayr Old English Decelerator on it and be done with it.
Id love to put real pads on, but I need to add lop to 2-3 guns so trying to have a quick cheap fix. I threw a cheap slip on pad on a cheap o/u that I dont care much about kind of as a test run. Probably pull it off after season.
I doubt it. Discoloration of wood is usually caused by sunlight. My experiences have been lighter wood turns dark and darker woods turn light. So I'm not positive but when I see that on older guns, I always think it's the rest of the exposed wood that turned lite, not the wood under the pad that turns dark.
I work in the flooring industry. It is common to preach to homeowners not to use rugs with rubber backing on wood floors. The chemicals in certain (not all) rubbers can off gas and stain finishes. Combine that with sun and discoloration is common. I would not be surprised if you saw varied results depending on slip on pad company and different stock finishes. If it were my gun, I would be taking it off after each use, rather than leaving it on for extended periods of time. Luckily for a gun stock, it is a relatively simple process to strip and re-oil or spray on a finish.