Other Bali and similar regional pieces previously posted on the forums for comparison:
http://vikingsword.com/vb/showthread.php?t=7547
http://www.vikingsword.com/vb/showthread.php?t=183
Personally I think Greg's piece is undoubtedly from the same area. The natural defensive geography of the Nigeria/Cameroon border area led to many diverse peoples coming into close contact in a relatively small area, often fleeing the Islamic kingdoms of the Sahel.