Which begs the question of why Oriolo named the character “Poindexter”. Either he was drawing on an earlier association, or he just thought it sounded funny, I suppose.
I’m not sure you need to have known a previous Poindexter to think of it as brainy.
I had never known of H. McCoy Van Devender before I met one. With no history whatever about the name, I and those around him always though of him as coming from a family with an estate, limos, maids, butlers, dressing for dinner, etc. Actually he could have lived in a lean-to with a mud floor, but I doubt it.