The pocket holes in your model have stayed as components, nested inside the caster mount.
Scale up a copy of the caster mount containing the intersecting geometry x100 or x1000. Make one of the complete pocket hole components unique, and do the same for the nested hole inside it.
Open one of the pocket hole components for editing - check that you can highlight the whole of its bottom surface with one click.With that face selected, Intersect faces with Model.
Do the same inside the other component.
Delete the surplus geometry that sits above the two surfaces.
Tried it without the scaling up, and without Make Unique, and some edges and faces seem too small to form properly - leaving holes - or deleting lines in one component would do the same in the other, leaving gaps.
The intersection isn’t perfectly symmetrical, which is why you can’t just leave the two components identical.
On further reflection I think it will be easier if you either explode the hole components, or cut them out of the component, and paste in place in the caster foot. THEN do the intersection, which will be geometry all in one context.