More thoughts:
Looking further at this pistol, I am more convinced of the associations to Ottoman style, and possibilities of Leige production for trade. Apparantly in Robert Elgood's "Arms of Greece,and Her Balkan Neignbors in the Ottoman Era" (London, 2009) , pistols with corresponding stock form are shown with an example noted from Brno (Czechoslakia) 19th c. While this was in Moravian regions part of the Austro-Hungarian Empire to cross influence into Ottoman regions in the Balkans was of course inevitable.
While trade grade weapons were being produced in various regions for the Ottomans, it does seem that Leige, in Belgium was also competing. Elgood notes in footnotes on p.224 (#15) that Burckhardt ("Travels in Nubia", London, 1822) had described brisk trade in sword blades from Solingen being sold in Cairo, and that 50 years later (i.e.1870s) there were cheap percussion guns from Belgium being sold in Cairo and traded into the slave trade markets in Shendy. While these were usually muskets, and obviously percussion, it is a good indicator that Belgian trade weapons were being received in Cairo (under Ottoman suzerainty) earlier and probably the flintlock type weapons as well. Other references have noted trade weapons from Belgium being traded in Cairo to slave traders from Darfur and Wadi in these times.
It is worthy of note that the use of flintlock guns remained in favor in remote native regions and colonial spheres for a considerable time after the advent of the percussion lock, primarily because it was far easier to obtain flints than percussion caps, as is my understanding.
With these weapons moving southward with slave traders, it would not be surprising to see a pistol of trade quality receiving this thuluth decoration and being used by an individual of some significance in tribal standing in these times of the Mahdiyya.
As always, looking forward to hearing more on this from those with knowledge on these kinds of firearms, whom I know are out there!!
. For further reference, the best reference on Balkan firearms is Robert Elgood's by far.
In any case, I hope what I have found is of interest thus far.
Best regards,
Jim