Remington M1903 4-1942

[cplstevennorton]

It's actually a Mark one stock. You see the cut for the Pederson device.

With the better pics my first thoughts are it has a very thick old coat of varnish. Sometimes the US Military and even foreign countries used Varnish on stocks to water proof them. Of course it could have been bubba back in the day as well, or any number of scenarios on how it got on there.

I do honestly think if you try to remove it you will have a mess on your hands, and it will end up likely looking worse than it does now.