Silver paint on Inter engine cases

I have attached a photo that shows the remnants of a "silver" paint on the cases of the International I am restoring.

As earlier conversations seem to indicate the possibility that at least some alloy cases were painted I am considering painting mine.

Another input from a source in Winnipeg,Canada claimed that some poor quality cases may have been painted.

I will attach another photo in a sequential email showing a repair that I believe is factory made on these cases.

This "silver" paint seems to have a green or golden cast to it. Not sure how well it will come through on the photo.

Anyone else seen this color or have suggestions as to this is a proper thing to consider for doing a proper restoration?

Also a question on the oil pipe nuts, such as part # A2/718 from plate B, plate # B.24 from the 1950 illustrated parts book. Should these type nuts be plain brass or plated?

Thanks in advance

Mark