slight bulge in side of boat
While it is unlikely that it has always been there, the bulge probably appeared in the first few years of your boat''s life. Pearson during that era tended to use a lot of acellerators in their resin and allow a comparatively short cure time. Tritons, also had a minimum of internal framing. Allof this would promote a tendancy toward the hardspot to be especially pronounced compared to later, and better built boats.
Whether you should be concerned with this or not depends on how you plan to use your boat. These hardspots tend to be more fatigue prone than other areas of topsides. Given the more brittle resins and laminates of the era, this typically would be an area of decreased strength over other portions of the topsides. Used normally this weakening should be of no problem, but exposed to the kind of thrashing involved in major long distance passage making eventually this could prove to be a problem.
As the prior poster noted, the bigger problem is the condition of the bulkead and tabbing. Pearsns of this era had structural bulkheads and they were often covered with Formica, which both can foster and can mask ongoing rot problems.