1.725" nut width is pretty standard I believe.
http://www2.gibson.com/Products/Acou...ard/Specs.aspx
My AJ has 1.725" nut, 2.125" fingerboard width at the 12th fret, and string spacing of slightly less than 2.1875" per my recent measurements. But it is their 'Mod V' neck. The J200 uses a different, more rounded profile IIRC.