Since Oregon is not a territory and its boot strapping to say they own so they can own it that argument does not fly against the plain language.
Its plain language argument and its not without its chance.
The granting of statehood did not magically transfer ownership of land acquired and owned by the federal government to the state any more than it transferred the ownership of privately held land to the state. That's the plain language of the matter, and pretending that courts are going to find otherwise now, after more than a century of contrary precedent, is just more evidence of Bundy's level of delusion.