Joe is right on all counts H, with the exception of the last, to an extent. The later B17G models deleted the radio room Browning .50 cal, and the mount was faired over with a clear Perspex patch, in the 'slot' for the gun mount at the trailing edge of the hatch window. However, as Joe said, the earlier G's did still retain the gun, but the hatch had a clear cover, unlike the open hatch of the F model.