It is like the Prindle, the strip and 2 bolts are one piece, If you can remove the other nut and see if you can force the piece up into the beam, remove and replace. If I recall the bolts were welded to the strip.
So I can't just replace a bolt? Its a strip that goes in there that I have to order from Nacra?
I would bet that it's two loose stainless steel bolts that go through a 1/4" or 3/16" aluminum backing plate inside the beam. I would expect to see enough corrosion on that plate to justify replacing it but you might get lucky and be able to reuse it.
You can get pre-anodized aluminum bar stock from McMaster. You will have the exposed cut end and the holes you drilled where the anodizing will not exist - but I would spray paint the exposed areas and use plenty of 42 or 5200 on reassembly. You should be able to get plenty of what you need for under $20.
McMaster anodized aluminum McMaster never links easily. From that link, choose Multipurpose 6061 alloy. On the left menu from there, click "anodized". Pick the size you need from there.
