That's a "SHEFFIELD" logo. It's a real piece if it has the FoMoCo, C5OE part #, and Sheffield logo. It should also have a couple more characters below or at the end of the C5OE #, most likely an A1. C5OE-6059-A1 was the new timing cover introduced at change L8 in June 1965 (have also seen May 65 - Aug 65 as the L8 date range) to handle the cast iron water pump. It will have seven ribs on top to support the weight. Pre-L8 timing covers for '65 had C4** numbers, and only two ribs at the top. Your C5OE cover was used on through 66 and into 67, so as s2ms said, you can check the date circle to see what you have.
PS: Bob Mannel's book "Mustang & Ford Small block V8" is an invaluable resource.