Ethnographic Arms & Armour - Two Fang swords.

Greetings

My most recent purchases, two swords of the fang.Their territory spans South Cameroon, Equatorial Guinea, Gabon and Congo. The specimen with the scabbard is 56.3cm and 62.1cm scabbard included. Both blades are quite thin, The one with the scabbard is 5mm thick at the hilt and 1.3 at the tip. The scabbard is missing a piece at the bottom, no idea if the scabbard was once covered with reptile skin or brass, no remnants to be seen.
Both blades have a full length central rib.
The specimen without sheath differs in blade shape.The most common shape is like the specimen with sheath, the typical wings or barbs. According to the site africanarms.com, the form without these barbs is older and rarer. My
specimen is 53.6cm long and 3.7mm thick at the handle and 1.5 at the tip.
These two Fang swords are the first I have held in my hands so I have no comparison in terms of blade thickness. There are plenty of specimens on the net and in the books I have with more massive blades and the thinner ones. I wonder, knowing that African blades were often thin in the period before they were overrun by imported European iron, if the thinner ones are older than the thicker ones or if they coexisted. Given the patina on the handles, they appear to be of reasonable age. Comments welcome.
Best regards
Marc