You can if you want it to keep coming off the rim ask me how I know. The point I was starting to make is that the totality original bike your rules are talking of don't exist or are in collections and don't get ridden.
Take my bike for example 1963 Greeves with your class rules frame, engine, carb ok. Exhaust is alloy so not allowed, Norton forks not leading link so not allowed and wheels are replica cub hubs with tubeless rear as got sick of messing with the bhc wheels that were fitted but they had alloy rims and were not original anyway.
So with your rules I might as well buy a Drayton frame kit and no one would get to see an actual pre65 bike as it doesn't fit in either category.