1969 340-s engine block color.

Guys I have one owner all numbers matching 340-s auto fast back This car has build sheet ,fender tag and window sticker. It has all the parts it was born with. With that being said the engine is blue the guy who owned the car since new said it came that way. I also have looked at several other 340-S cars restored OEM that also seem to have this color engine. Is this right none of these cars had a orange or Red block from each one I have seen. But I find no books that support the blue color for a 340 4BBL in a A body.....Color answer needed ...