What is the absolutely correct blue engine paint color for a 74 Duster?

For comparison, here are a couple photos of the slant six in my grandfathers 71 Satellite wagon. As it happens it's parked right in front of my hangar just now. This car hasn't been driven since the late eighties and it's been in the family since new, so i can guarantee it's never been repainted. Obviously this engine's paint has seen better days, but this looks nothing like the blue seen on the 360 valve cover above. Not sure what to make of that, but there it is.
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Tanker, what is this color on the rectangular sheet? Is it from a spray can? Thanks.