A piloted counterbore (with pilot to fit existing holes) is the easiest and most precise way to open up pre-drilled holes for pillars. Follows the existing holes, so no need for precise location on a mill or drill press- it could be done with a hand drill just fine.

As to whether or not it's required, that depends on the level of accuracy desired. Laminate is still "wood", it WILL be affected by humidity and temperature changes.

What you didn't mention, is what's most important IMO- and that's a good, stress-free bedding job for the receiver. I consider that mandatory in a Boyd's stock, pillar bedding optional. Receiver fit isn't going to be precise enough for the receiver not to be stressed when the action screws are torqued without bedding- which will be exacerbated with the environmental conditions.