Hi there,
It's totally up to u whether u want to sand it down or not.
In order to save times and works, i won't recommend it. =)
Lacquer back the headstock, it'll be consider as refinishing.
I used normal Spray can Nippon PYLOX clear color for lacquer.
There will be other methods that u can google it.
In general, u will have to spray for 10 ~ 20 THIN layer of clear coats.
Then wait it for completely dry for FEW days.
By using 1500 grit sandpaper, wet sand it until u cannot see the edge of the decal. (Here is the reason why u need to spray so many layer of clear coats.)
finally, use car polishing compound/wax to polish until it become shinny!