Normally when im doing up a PF, i'll make an effort to remove and at least re-level the inserts if they are ones with lettering on them. well these ones are all sunken and concave in the middle so my usual trick is to remove and sand them flat, again (3rd pic show this). so being that these inserts all have lettering that would have to be preserved or re-done, i made scans of one of the insert's 'when lit' text and of the middle A B &C inserts so i could make adhesive decals if the text to reapply once i had them sanded nice n flat.
Anyhow the pics show some of the inserts removed, and the adhesive decals printed ready to be reapplied. the insert flattening process, first using 80 grit sandpaper (pictured) then 400 and finally 800 grit paper, and finally one of the inserts wit the decal applied. Btw.. This insert is the 'extra bonus' insert, which when i removed it using a heat gun to soften the glue, and a socket and hammer tp tap it out.. i managed to deform the insert in the heating process
luckily i was able to save it in the sanding flat process!!