I use Chambers finish and put it in all inlets and with a q tip in all holes. I had a rifle that was basically unsealed and the stock swelled and warped during a period of humid weather. That experience is why I try to totally seal my guns.
My two personal rifles, a 54 that's 25 years old and a 40 that's 20 years old are both sealed this way and have been out in all kinds of weather with no wood problems at all.
So I can't really see a reason not to totally seal the stock. Just because it might not have been done back in the day doesn't mean we can't do it today.