I did by lightly heating a field tip while holding it with vice grips then screw it in and slowly pull it out. The luminocks needed a light sanding so they would fit right and you have to line up the contacts with the vanes so they are parallel to the rail.That is explained in the instruction.
Hope this helps
i asked the same question on the Excalibur forum and got the same answer. (using heated feild tip) i never bothered doing it as decided against the luminocks. This is a great site but you might also want to sign up on the Excalibur site. Really good info there from guys with the same equipment.