Jim,
I realize it's a big stretch, but certainly plausible. Thanks for not hooting me down. The Freemasons were attractive to certain Ottoman elites and middle class professionals. Many lodges were established in Ottoman cities including those in North Africa in the 1835 -76 era.The first Lodge was established in Tunis in 1861 under French influence. You are correct that it is a stretch for educated elites to be carrying marked swords in the interior, but we don't know the provenances of the marked sword blades that have been shown by our Forum membership. Maybe Briggs' examples came from links to some of those elites.
History of Freemasonry in Tunis:
https://uglafrica.org/tunisia/
Other reference works, some major, are available on-line.
Ed