For James: the GNW is not my 'period', but from a cursory look into A.V. Viskovatov (and some dodgy quick 'translation'), it appears that all flags had gilt (golden-plated) finials, with two cords (with tassels) in the 'metalic' colour of the unit--e.g., gold or silver. (See
http://listat.ru/T02/T02_02.htm - click through the 'blue' highlighted urls to view the illustrations of cords & tassels on the flags.)
Certainly, in the SYW and Napoleonic era, the same regime continued for flags, with gilt finials (spearhead-shaped), but with silver cords and tassels as 'standard' on all units bearing flags. At different stages of evolution, black and black & orange threads were sometimes intertwined with the silver in the cords and tassels. (See Opsrey MAA Series #297 and #078 for details.)
In addition, and as hinted at by Dave above, units receiving special 'battle honours', such as awards of the Order of St. George, might receive a
cravat of orange, with three black stripes, to tie around the finial. However these cravats were
in addition to the normal cords and tassels--not 'instead of' them. In the case of a regiment receiving the St. George award, the finial atop the flag staff would be changed for a special guilt one with a white enamel cross enclosed by a 'hollow' spearhead outer point (rather than all gilt).
Hope that helps a bit.