The bench rest guys regularly glue the action into the stock. When they need to remove the action from the stock, the action is heated with a hot air gun to soften the epoxy bond to the metal while applying pressure. Sometimes they use a jig to push off the stock, pulling the action straight up. You might ask in the gunsmithing section of Benchrest Central for guys that have done it.
So you should be able to see the threaded holes for the action screws front and rear. Is there a screw in either one of them? If not, it is likely a glue in. If there are screws you could be in trouble. That would indicate that the pillars were mounted to the action and then glued into the stock. If that is the case and you can't access the bolt heads from the bottom, the best way to remove it would be to drill/mill the pillars out being careful not to cut into the action.
