David, excellent compilation of material on the cobras, and the more I look at this, the more the hooded cobra image seems logical. Fernandos addition of the extremely compelling stylization of the antelope corresponds to those illustrations I have seen of these masks in Mali.
I think it is important to reemphasize the concept of 'representation' in the stylized images of sometimes hybridized creatures, in this case in African material culture including weapons. Ideally, we have hoped to identify this sabre by linking the stylized zoomorphic image on the pommel to creatures significant to certain tribes in certain regions.
Although there are compelling suggestions to what creature this pommel might be, without a provenanced example to corroborate where exactly this sword might be from, we cannot be certain. The overall style seems to resemble the regalia type swords seen in a number of instances in West African and Sahelian regions, and the hanger type swords seen in the work by Bivar on Nigerian arms and armour (thanks Tim
are good examples.