Ken, the to shelf stuff for Hypalon is Bostik 2402. I've only found one place to get it in the US (besides through GSA, but that's not an option here). E-mail or PM me and I'll point you in the right direction - I'm not going to post links or information here. This is the same adhesive Avon constructs their boats with. Good stuff, but the VOC's are ridiculous. This is no kidding need a respirator stuff.
With a better idea of what, exactly, the problems you're trying to fix are, I could probably offer some advice. Photos would be VERY helpful. If you're looking to just reglue the wooden transom back into the tabs that hold it - might not be so easy. Higher end inflatables use several layers of tabs going in different directions on different pieces - not a simple 'socket' arrangement. Again, photos would be good here. Also, if the bonding has completely failed anyways, might as well fabricate a new transom now. Hardest part of the job is reinstalling it, and on a boat that old, odds favor replacement being the good bet. Kind of like replacing the timing belt when you're having the water pump done, or replacing the water pump when you're having the timing belt done. You're there anyways, the comparatively minor cost versus repeating the bulk of the cost to access that point in the process again makes sense. With the ready availability and easy application of modern epoxy resins, high grade marine plywood is not as necessary as it used to be for such parts.