Typically, on the factory sintered steel Mark III hammers, the color case doesn't show much except on the sides.
Since there don't seem to be any file or grinding marks, and the finish appears to be factory original, I'd bet that this is an uncatalogued, limited production model.
The problem with the 2" Lawman is, it's the ONLY Colt that used that exact grip.
Due to the special rounded butt frame, no other grip BUT one made for a 2" Lawman will fit.
The 4" Lawman used the full profile square butt and the grips even on the Lawman don't interchange.
Best advice is to contact some grip makers to find one who offers or will make a set for your 2" Lawman.
When contacting them make SURE they fully understand this is a 2" Lawman, and that 4" Lawman grips won't do.
A1A: For original 2" Lawman grips, Ebay is your friend.
They show up there fairly often, and usually either don't sell at all, or sell fairly cheap.
NOTE that the 4" Service style grips also WILL NOT fit a 2" Lawman.
ONLY 2" Lawman grips will fit.