Randy, I'm not an expert on the C&O. But most of the photos I've seen suggest their Berks a.k.a. "Kanawhas" had a large sand dome AHEAD of the steam dome, as on a postwar 2026.
[Aside: I'm convinced that the C&O Kanawha, with its large sand dome and air aftercooler on the pilot deck inspired retooling of the venerable 1666 into the "2026" circa 1948. If you look past its O27 size, in many ways the 2026 captures the style of real Berkshires better than Lionel's 2-8-4's did!]
Fast-forwarding to 21st Century scale models, MTH's version has the authentic C&O dome arrangement. Lionel's C&O Berk, although handsome, appears to be based on the NKP and Pere Marquette common design with a large sand dome centered near the middle of the boiler. These are pricey locos, so if you're looking for the most accurate model, you might want to hold out for a MTH version. If you don't care about pinpoint accuracy, they're all mechanically sound, fully-featured smooth runners and powerful pullers.
Let me close by saying that I love Berkshires! Even more so than Hudsons, they are the "big, black steam locomotives" in my childhood storybooks brought to life. That squat, chunky boiler set over medium sized driving wheels, big square cab and rugged modern appointments never cease to capture my imagination. The fact that they were used all the way through the transition era and continue to operate in modern excursion service mean that they're at home on any layout! -Ted