That cover does not have a Chevrolet script on it. The only factory original 4 screw covers that I have ever seen with out a script are from Canadian pontiacs. I have one. The entry level motor for the 55-62? Canadian Pontiac passenger cars was essentially a 55-58 bypass style 261 Chevy truck block. Those motors used a plain valve cover. With the exception of the chrome aftermarket covers currently on the market, the Pontiac motors were the only chevy based motors that I have seen with that kind of plain cover. So it looks to me like it’s a Canadian cover modified to fit an early head motor or a later head with the early stud arrangement installed.
