Wow, I have no expertise on these other than to say they are definately British and my first reaction..... George III American Revolution if that is at all possible and if they are original. G R stands for George Rex ( King George). They strike me as being British grenadier mitred helmets from two different units. The green piece has the white horse of Hanover stitched to it which makes sense as the "Georges" (Kings of Britain) were Germans from Hanover originally. They employed units raised from their lands in Germany for example The Kings Legion from Hanover fought for the Brits in the Napoleonic wars. Consequently, the Kaiser awarded these regiments with special battle honours on their pickelhaube helmet plates "Waterloo" for example. This is the best that I can do...hope this helps. I am sure that otheres on the forum will be able to provide much more information. Regards, Brian