I, too, would wait and take Mica's advice.
IF I were to hazard a guess I'd say you'd have to back out the threaded inserts (I'm sure they have wood screw threads on the outside), fill the holes with a wood/glue mix, and once dry and solid, use your new pickups' screw holes as a template and install the proper inserts in those new positions. I would be in no hurry to enlarge the pickup holes in your brand new pickup(s).
But as always, I'd go with whatever Mica tells you.
J o e y