Somewhere in another thread, I took the idea of the katana and brought it down to the base concept: it's a weapon that's only to be used by a certain caste, who must follow a specific code, and it's made by folding fairly poor-quality steel a zillion times until its really strong (I realize it's more complicated that that).
So in a fantasy world, you have a people--which can be of any species--that uses a weapon made of what others would consider a sub-par material, but the material is treated in such a way that it's actually really effective. And only a certain group of people within that culture can use the weapon. The weapon can be made of anything, from poor-quality steel to magic wood to monster teeth, and the subgroup can be anything from a caste to a specific order of warriors to people who are all born with one purple eye. And the code they must follow would probably take at least some cues from bushido, or European chivalry (which is actually quite similar), but could easily include other details based on whatever species you're dealing with.
You could still be probably accused of appropriation because you were using what they call 'coding', or words that have traditionally been used to represent a specific group (in this case its a part of that groups culture).
Would the accusation come off as silly? To me, yes. But there would be a segment who would see it as anything but.