I recently inherited an old ithaca 12 guage serial 339xxx in pretty good shape, a little case color left but with a small chip out of the upper left stock. I want to clean it and can not get the forend off. It has a splinter forearm with a single machine screw just forward of the hinge. I have removed the screw but the forearm does not budge and I do not want to force it. Any additional info on the gun would be greatly appreciated.