There is a problem with using a casting direct from original rifle parts.
The old timers made mistakes too and it shows in the castings sometimes.
One I know of looks like the smith either had a bad casting, goofed on the carving behind the cheek and had to file it off or lacked enough wood and filed the buttplate to too flat a contour on the cheek piece side.
Sometimes shrinkage is allowed for and sometimes not. I would guess that most do, now, Goehring I am sure always has.
Some parts are cast from copies of original parts and this makes shrinkage even worse.
If the shrinkage is not properly allowed for the buttplate will be smaller in all respects. If the original rifle one is trying to copy has a 12" pull as some do and the buttstock is stretched to 13.5 and the buttplate is 4 3/4" rather than the 5" on the original was then it will be impossible to make the buttstock look close to that on the rifle the stocker is using as a guide for the project.
So "cast from original parts" can be a double edged sword.
For example, the "Hawken" buttplates, most of them anyway, are really just a caricature that is some moderns idea of a Hawken or cast off a buttplate that was a "goof" originally and are a pet peeve of mine.
Dan