Hi Derek,
I have no reason to doubt the Chinese ID.
Just a quick footnote: I have seen a few Selkirk weights without any markings (and they were Selkirk known limited edition weights). I was told that these were just produced and yet to be engraved with the normal markings when Selkirk closed in 2006. I do not know whether they were sold to the public, or given/acquired by the staff after the closure, but I have come across a few in Scotland since I started collecting.
Also I own a Selkirk lim. ed. blue lagoon with a rather rough and matt polish underside. According to the markings, it is the Master Copy for this limited edition. If there is no doubt that my weight is indeed a 'blue lagoon', I have never had its Master Copy status confirmed. Still, it has a matt underside.
SophieB