"LOL.."Correct" Engine Color is always a hot topic." - to say the least.

No one (not even in the VCCA) has come up with any GM-document with color codes.

The only GM statement of an engine color that I have seen is "The new engine is painted gray . . " in the 1954 Chevrolet Truck Engineering Features manual/booklet. I'll interpret that gray to be a different/lighter color compared to the darker gray-blue used on the earlier low-pressure engines.