I just removed most of the finish of a 1920 era LC Smith field grade stock with nothing but denatured alcohol and a cotton reg. Left most of the stain. Varnish was all flakey and wrinkely but clean it up pretty good.
What this means is that the finish was not varnish. Denatured alcohol won't remove varnish. What you removed was almost certainly a shellac finish. Old shellac often gets flaky and wrinkled. Your alcohol dissolved the old alligatored shellac and some of the thinned shellac probably went into the wood.
I also found a shellac finish on a 1920's 16 ga. L.C. Smith Field Grade gun that I picked up at a gun show. The stock looked like crap, which certainly contributed to the low price. This finish was easily removed with alcohol, right down to the wood. There did not seem to be any other finish underneath, so this makes me wonder if Hunter Arms didn't use shellac on some of their guns, because it didn't appear that the gun had ever been refinished. I also bought a Baker double that had a very alligatored finish. I was sure it was refinished with shellac, as it was even slopped onto the metal. I removed it with denatured alcohol, and found that the original stock finish underneath was still intact and in good shape.
