Congrats on the newest member of you family. I also have a vintage Tri-Hull and love her to death. Having the age it does take a bit of time and do some hull inspection. In fact just to be safe side I recommend applying a few layers of fiber glass along the keel, for the just because factor.
How is the decking? If you notice any soft or punky wood, I'd suggest pulling the floor up and replacing it. Surprisingly, it's not that difficult to do and will give you a chance to view the condition of the keel wood below.
You'll come to love your tri-hull, it's a great fishing platform.
Again congrats.