Big difference between "Re-barreled/re-stocked" and "Custom" IMO. Similarly, I believe there is a large expanse between "Gunsmith"and "Gunbuilder".
I have a few rifles that have been re-barreled and re-stocked. A M70 SS Classic in a McMillan w/Lilja chambered in 257Wby. I also have a Lawton action left port, right bolt, single shot, in a McMillan Tooley MBR stock w/Brux bbl in 7WSM that I still don't consider "custom".
This is "Custom" IMO. Commissioned by the wife of one of the American judges presiding over part of the Nuremberg trails in the late 1940's to his specifications:
In 7x57 of course.