Zodiac (which own Bombard) had a particular issue with their PVC boats mid 80s on, in that the tube seam was on top under the rope lace cuff. With heat and expansion this seam was particularly vulnerable. Came to light state-side where their summers were half decent. Zodiac eventually moved the seam under the tube in the water.
Useful to know, but I wouldn't worry about it uneccesarily. It's 30 years old, don't spend too much, and any areas starting to lift, then Polymarine 2-part PVC glue with the right preparation can rejuvenate an old boat.
Areas to look at are the transom as mentioned, cone ends, inflatable keel where it's folded over and glued towards the transom. I'd replace the diaphragms in the valves as a matter of course as this is a serviceable item.