Snap-in bearings are also readily available, but if you want the split bearings, you could certainly drill out the holes. I do see some problems though:
- holes must be drilled exactly centered, which is tough considering there is already a hole there. Makes it hard to precisely center the bit because there is now air where you would normally put your centering mark.
- holes must be drilled exactly perpendicular to the sidewalls, otherwise bearings will bind.
- drilling through laminate is tough to do without chipping. Not a huge issue since the flange of the bearing should cover up any tearout.
The best way to avoid the three problems listed above is with a forstner bit and a drill press. Hard to do on an already-assembled table. Maybe new snap-in bearings will be good enough?