I ended up doing this with my F14 - I leveled some of them but heating them. I actually removed them, sanded and glued back in. but most of the 'arrow' head inserts had cracks and I didn't want to risk completely breaking them as there are not any replacements available that I could find. Most of these were barely raised (did try heating and pressing some down). Applied a couple coats of clear with decals and then decided on trying out one of the playfield protectors as I didn't want to mess with adding anymore coats of clear.

In hind site I probably should have pressed on with more coats of clear to level the surface (did have an issue at one point with the clear and didn't want to fuss with it anymore (or make a really big mess of it)), but the protector seems to work just fine as well.