Agreed!
Make sure you take at least a clean skin chip off the face too, for assurance of both radial and axial runout being minimal.
Machine the OD so the collet chuck is a very snug fit at first. Check runout of the ER taper at that fitment, and if it's not true you'll need to take off the equivalent of 2X the measured runout to have enough clearance to "tap it in" to true before you really clamp it down.
Make sure you take at least a clean skin chip off the face too, for assurance of both radial and axial runout being minimal.
Machine the OD so the collet chuck is a very snug fit at first. Check runout of the ER taper at that fitment, and if it's not true you'll need to take off the equivalent of 2X the measured runout to have enough clearance to "tap it in" to true before you really clamp it down.