This is a very interesting thread. Tribal people might make a weapon from local and found foreign pieces. it is still an "ethnic weapon" also tools can be weapons. Many battles when the peasants where sent in they would most likely fight with tool like weapon {spades, forks so on}.
This is a difficult area especially when it comes to trade. It is so easy for a vendor or buyer to say this or that is not right. However knowledge {culture, history, technique and region influences} and searching for real examples should make it easier to spot the cobbled together fake pieces. Anything off standard is always open to blinkered questioning which is a shame. On the over hand it can mean good piece for those on more limited means.