So I took a drive and looked at that 63 again. It has no tach. But it does have this exact set-up -
www.americanclassic.com/images/GCL60G.gif American classic charges $385 + core charge for that cluster.
The picture in my owners manual of the 2 1/2 ton panel looks like that except it has a tachometer in that unused circle on the right and an air pressure gauge in that same space to the left.
Looks like I'll be using the dolphin gauges.