My take on this is the elev. is minus the monocote. You do not mention if this is a flat or airfoiled elev. Anyway since it is bare balso it should very easily be straightened. Fasten down to workbench by pinning, weighting. clamping whatever needed. Bend warp out and block it a bit over what may be required to get straight. Mist it with water to dampen. Let set there for several hours or dry it with heat gun. Should be fine and ready to monocote.