I have a set of the finned covers which the previous owner swore up and down were original mid-60s vintage. (I can't verify that but they were certainly dirty enough when I bought them to have been original.) Anyway, I had the same problem with clearance on the Dove end stanchions. A little light work with the Dremel tool provided the necessary clearance. I also found, with the original chromed pent-roof covers, that the fit over the end stanchions was an interference fit.
Incidently, the flat bottoms on the aluminum covers don't match up well with the mating surface of the Edelbrock aluminum heads and they have a tendency to dribble small amounts of
oil. Even with the gaskets glued to the valve covers, they don't seal very well. Gosh, an FE engine that leaks
oil.... What's this world coming to?