There are some interesting pictures of civil war era armored tractors at http://www.darkroastedblend.com/2009/01/ugly-belching-steam-powered-tractors.html scroll down a bit
Only one is armoured car from Civil war here: Allis-Chalmers-Poutiloff (project of colonel Goulkewitsch) - furst name "Achtitetz", later name "Krasnyj Peterburg" (Red Petersburg), in service 1916-1921.
All others armoured tractors are later 20 and 30 years.