TOPIC: rub rail piece

Spotted an aluminum corner piece off a '66 Starcraft Holiday for sale...however, there are no measurements for the thickness of the rubrail it fits on....i am hoping someone out there can tell me if the rubrail size is the usual standard for mid-sixties boats, like my project. Hate to spend 40 bucks on something that won't fit. The seller refuses to answer me on this. The size i need is about an inch and a quarter or so.