Thank you ziomanno for taking the time to reply.
This is very interesting information that I can add to the description of this helmet for cataloguing purposes.
I suppose it is difficult to tell when a repaint has been done, but at least I can say that this helmet probably was always in the navy use in one way or another.
I can tell that the chin strap was removed for the re spray as there are no signs of paint on it plus the bales are painted. Perhaps this is why it seems to have strange nickel/stainless steel rivets. Maybe a renewed chin strap at the time of spraying, will never know for sure.
You could be correct about a rank insignia being removed for whatever reason.
Thanks very much again