Hamilton shows a Type C with a rear sight in is book :Colonial Frontier Guns, by T. M. Hamilton.
Now a few years back a English Type G was uncovered in Florida which also had this same type of sigh as well as a dove tailed front sight .
The gun was documented by James B. Levy ,Historic Conservator, Fla. Dept. of State
You can read and see photos about it here
http://americanlongrifles.org/forum/index.php?topic=4828.0 Jack Brooks had an original Type D barrel as I recall that also had a V type rear sight . He sells the casting for that sight
You can see and read alittle about it , here
http://americanlongrifles.org/forum/index.php?topic=23679.0Now past that . Link , in his Thesis; the Flintlock , it origins and development
Documents a great number of times , rear sights on French guns .
The sights range from very high end to very simple .
What they all have in common is that they are a butterfly/ Vee , type rear sight
Very much like those found on some English trade guns .
The difference IMO seems to be that the French rear butterfly sights , seem to be soldered on while some of the English rears are clearly dove tailed
eather way , they are a very simple sight to make