There are two ways to put carved ornament on a drawer front. You can cut it into the front itself, or you can carve it separately and fit it on. Both are proper work, and they produce different objects.
Carving in place means the ornament and the ground are one piece of wood, and the ground has to be taken down around the design - so the whole front ends up modelled, with shadow across all of it. Carving separately leaves the front untouched and puts the relief only where you want it.
On a white and gold piece, the second way is the right one. Gold needs a flat, bright ground to read against, and a modelled white surface behind it would compete.
The difficulty is the curve. These drawer fronts are serpentine, so a mount fitted to the centre of one sits on a surface that is falling away in two directions. A flat-backed mount would rock, leave a gap at its edges, and eventually work loose.
So the back of every mount is hollowed to the exact curvature of the spot it will occupy - each one shaped to its own position, not to a standard. Move a mount two inches along the front and it no longer fits.
Our carvers number each mount and its location before anything is glued. The mount is then bedded so its edges meet the white surface with no visible line, which is the whole point of doing it this way.