This same thing happened to me. The difference was that I did use a good release compound, and i did get it off. I filed a bit off and managed to get it to fit in again.
yes, i took out the magazine box, wedged in wood chips at the back of the action, and whacked the barrel very carefully with a heavy rubber mallet.It didn't matter too much, but the thing came out perfectly. later in the year I replaced it, now I have an entirely perfect short action BDL stock from the sixties, back when it was real walnut and cut checkering, and a nice looking figured walnut stock from fajen.
You MAY be able to do that as well, shimming the rear of the action as you put pressure on the barrel. That is only if he had use the release agent after all, and the stuff isn't packed too tight. Again, I wouldn't screw around with it and destroy a perfectly good stock unless you absolutely have to, unless you just want to replace the stock. You've had the suggestion to check the accuracy yourself and see if it will fit your standards, and I think that this is the only mandatory thing. Relieve the barrel channel if you have to, test fire with a few brands of factory ammo.