My experience has been that they sometimes but not always put a flash coat of black on them. They were then machined on the front where the code was stamped as well as the two flat surfaces where the outlet lines were attached. I restored ours with a light flash coat of black and then machined the surfaces as can be seen in the photos. Our original hold off valve showed no signs of any paint on it so I restored it as such. I found no date stamping on either piece.
Last edited by SS427; 03-09-2019 at 12:48 AM.
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