As mentioned above there definitely must be different Circa 1850 products. As over the years I have found none of the standard paint stripper products will even soften epoxy finishes, and Browning, Winchester, and Remington all use epoxy based finishes. I know there must be a product that will bubble and lift epoxy finishes but I have never found one.
Scraping and sanding was the safest way. Years ago I had used a method of using a hand torch to bubble up the epoxy finish, let it cool and it turned very brittle, and scrapped off very easy. But it was a very tricky process as you could easily over heat and darken the wood. I have never shied away from sanding a stock, in fact there are very few I haven't. You just make sure you don't over do the sanding and never sand without the butt plate on or you will round the edge of the butt and it will look like hell when you put the plate back on. My opinion is the finishes that are currently used by Winchester/ Browning hide far more features of a nice piece of walnut than they enhance. Once you get that epoxy crap and it's stain off and apply a good oil based finish the grain is truly enhanced and exposed.