Added a stamped "serial no" to the back of the headstock, filled with Ebony Timbermate, let it dry, and then sanded back with 240 g paper.
Also levelled the frets (upgraded to an aluminium fret block), filed, checked with a fret rocker. Relevelled, refiled, rechecked everything two more times. Then polished with a fine scotchbright pad and 0000 steelwool.
This time I also tried a new fret end file to tidy and remove the fret end burrs - after watching the Stewmac and other videos.