I have some Civil War era acoustic guitar tuners for sale. These are very hard to come by. It would appear that they have the original buttons. The plate itself measures 4.25" in length. From center to center of each post is roughly 1 5/16" and there is a 1 1/32" gap between them. This is slightly narrower than the more modern Kluson/Waverly tuners of the Prohibition era and should be taken into consideration. The buttons don't all turn perfectly straight but these tuners are in greats shape especially considering how old they are.