Before you leave it and let it be, take a look at the inside full length plate. I had one fail on my boat. That left only the short outside plate and one screw holding the rig. If OK, then Matt is probably right, the load on one screw is not going to change much by tightening. I was lucky, all the screws on both hulls came out and returned cleanly. Also note, one screw and that "helper" plate had been holding the rig for a while, as the cracked part was clearly rusty from time apart.
By the way, all broken parts on my boat were either caused by or contributed to by Matt Miller, and yet the boat lives on. (not 100% accurate, but close)