Ruger did get in on some salt cured wood as did Winchester.
W/O testing the wood blanks for it, you really can't tell just by looking at the stuff.
It's not that it' was a new (at time) discovery for how to quickly cure the wood. The furniture industry and others had been using it for a long time..
Some other pre WW2 European guns from smaller makers will show up with the nasty rust pitting under the wood line as well,,all due to salt cured wood.