1. I own potter #471 and replaced my rub rails from WEFCO Ruibber Manufacturing Canago Park CA. Their website has all of their products in same size profile on view.
Their toll free number is 1 800 854 1220. Person on the order desk was most helpful when I made inquires after viewing the website catalog. Service was great and am most pleased with the product. Ray (WWP # 471 Proud Mary )
2. TACO is another brand of rub rails and is sold by West Marine.
I replaced he original wooden rubrail on my 1967 P14 withTACO black vinyl rubrail that takes a vinyl insert, but I used three-strand nylon rope instead of the vinyl. The rubrail fit perfectly on the type of cabin- to-hull joint used on the early Potters. Your boat may be different.
They have it in white and black. It was over a year ago but I think the part number was F-113 or F-115, I cant remember (the F was for flexiable) David