F and F boat

[Dutchman]

My F and F has a LARGE gunnel with a slot down it for bolting accessories using t bolts or carriage head , with extrusion for rigidness. I tried the aluminum extrusion used by all the major production boat companies, but my gunnel is flat across the top and theirs is angled. This leaves a gap between gunnel and extrusion (see photo) F and F is out of business. Does anyone know where I can buy the extrusion that will fit a F and F? Want to add some accessories.