Johnboy; the slide and trigger housing are Inland. The 'W' on the bottom of the slide is an inspector's mark - internal Inland or Packard (Packard for Inland - 'P.I.') mark, not gov inspector. The slide is called a 'Type 5' and started showing up around 5.0. At least that's what I think. I have a 4.927 with a Type 5 but I don't think it's original since it also has many other updated parts. However, if your carbine is truly a 'time machine' and is in unmolested configuration, I guess it is what it is.

As for the stock, you might consider cutting your
linseed oil
50% with turpentine which speeds penetration. I would give it a few light doses, inside and out, then rest it for a few months. Get a film of lubricant/preservative on all metal surfaces too.
Wow. Somehow I missed the pics before posting. Looks like you have the situation well in hand on the stock oil and gun oil. It's beauty for sure.