You don't need a special rub rail, you need to close that gap and re-attach. I had the same issue, I think. Pictures would be helpful.
Here is the process I think you should take.
1. remove any leftover adhesive in the gap between hull and cap.
2. Replace it with 5200.
3. Re drill structural bolts and screws to hold together hull and cap. Your existing holes may be ok, but I doubt it. Check this. On my 89, there are structural bolts that hold together hull and cap, and screws that hold rub rail on, as well as provide secondary holding power of hull and cap. You want to make sure both have good grip, and are both actually going into both hull and cap. To make sure these go through both hull and cap, you're going to need to close that gap. I accomplished this by having my helper stand on the gunnels while I drilled and put screws in, section by section. Shoot 5200 in to screw/bolt holes as well.
3. Send the bolts through hull and cap, and follow with rub rail screws. If you can access the hull in sections, through bolt them.
I did this a few weeks ago, seemed to work. Hopefully you can learn from my mistakes, I didn't take out old adhesive from hull and cap, or thru bolt. Realized when it was too late that this would've been better.
