Pewter buttons for your uniform coats: you might want to check out this page. http://www.milwarehouse.com/18thcenturybuttons.htm

 

I would say we are looking at the 3/4" and 7/8" flat plain pewter buttons. The 7/8" for the lapels, cuffs and pockets and the 3/4 for the collar and epaulette attachment buttons.  The pictures of the original coat actually shows a smaller button say 1/2" to hold the collar to the lapel and the epaulette to the collar. But we need to find a good source for that, perhaps either Roy Najecki or Townsend.