The risk in bolt on keels or bolt on ballast is that the bolts fail either from corrosion
or breaking in a grounding. The difficulty is that there's no easy way to check the bolts except by dropping the keel or ballest.
In thie OP's case, the bolts are not stressed as they would be with a long bolt-on keel and would be supported by the keel in a collision
. Still, it's an old boat. The most conservative thing would be to drop the ballast and check. Second best (and probably good enough in this case) is to torque the bolts to the manufacturer's spec. If one is very weak, it will break during the torquing and spin.
The Cheeki Rafiki lost
her keel off Nova Scotia
causing the death of all four crew (who were professionals). The evidence points to several bolts broken in earlier race
groundings that were not later checked. The OP's bolt on ballest is an entirely different arrangement from this racing
bolt-on keel and not prone to this type of failure. If you'd prefer a sleepless night tonight, download and read the terrifying official MAIB report