It took me a few days to locate a gold specimen to compare with.
When I purchased my bronze specimen. I knew the reverse was correct die for the Hawaiian Mint 18K 21mm gold. It was the obverse that was puzzling.
After taking a few pictures of my specimen and locating an actual gold specimen, it can be confirmed that I have a bronze trial piece. As for the the claim that my bronze trial piece is one of five, it maybe true, its not confirmed that there were only 5 struck.
In the image, directly compare Kalakaua’s hair strands. They are exactly placed. Click image to isolate the image, then click again to enlarge.
M&R indicates that 2M-141 had 50 gold specimens struck.
RHM database indicates only 26 gold specimens were struck (listed as 1982 Kalakaua 21 mm 18K Gold).
There is no public record that any bronze specimens were struck. Coin holder from seller indicates only 5 were struck.