I received the following comments from a curator of a very respected Native American Indian Museum.
Interesting piece! I can't say fershure that it's Tlingit, nor even that
it's Native-made, but it certainly looks as if it's modeled on a traditional
Tlingit dagger. The workmanship on the blade is more crude than most of the
ones I've seen from the Skagway workshop, but I've seen images of
equally-crude Alaskan pieces clearly (and hastily, I think) made for the
tourist trade. I can't figure out about the copper, why it has all that
pitting in it - suspect it's some kind of commercial sheet copper but don't
know why it's so rough. ....
The pommel is strange - is it supposed to be copper also? It looks more
like carved horn or antler and, again, seems to be an attempt to look
Tlingit but whoever did it was far from masterful. It looks, in a weird
sort of way, like those Greenland masks that were collected in the 1920s or
1930s - there was an article about them in Arctic Anthropology but I can't
lay my hands on the citation. I guess, though, it's intended to be Tlingit
or at least Northwest Coast - the ears and the treatment of the nostrils in
particular kind of suggest that.
I couldn't begin to put a date on it - although, interestingly enough
there's a collection of Tlingit masks at Princeton that were acquired by
Sheldon Jackson in the 1880s and they're pretty poorly carved, painted with
bright enamel paints and then shellacked or something - When Erna Gunther
first examined them in the 1960s she remarked that it was astonishing that
so much bad work was being done so early.
Need I say that the blade is decorative only and would never have been
functional?
these are just my thoughts...

The last comment about Sheldon Jackson acquiring the Tlingit mask that are now at Princeton sort of ties in my provinance about this piece being acquired by Dr. Jackson in 1905.
tomahawak