You are quite correct. The theory behind the Emancipation Proclamation was that it was a war measure. In essence it confiscated the property of rebels. It expanded on previous Confiscation Acts that put somewhat less extensive abolition measure into effect.
Lincoln made no attempt, in this proclamation, to free slaves in areas not presently in rebellion, on theory that he had no power under the Constitution to do so.
It should be noted, however, that Lincoln repeatedly encouraged and supported abolition efforts in Union slave states, including offers to provide federal funds for compensation of slaveowners.
This resulted in emancipation in all but two Union, and several occupied, states before the end of the war. So that 13A freed only about 50,000 slaves in KY and DE. 98.75% of all slaves were freed before the war ended.
Thank you.....