Good work so far, and yes, there's still time to get into the PTo group Build, as the closing date had been extended.
Those etched-in stars are a throw-back to the late 1950's I think, when some companies did that for all the aircraft markings, so that they could be painted in.
To fill the marking without destroying the other recessed detail, use Johnson's Future, and mix in some talcum powder, until it looks like a sort of porridge. Brush this onto the reccessed areas rerquired, wipe off any excess with a wet finger tip, and let it harden for an hour or so. then, gently sand it. the raised surface of this 'filler' will crumble and go dusty, but the filled area should be perfect. If any of the surrounding detail has accidentally been filled, use the pont of your scalpel/craft knife to gently re-scribe it - it should be very easy to do.
By using Future instead of normal, enamel -based gloss Varnish, it allows a thinner 'mix', which will be better for small lines and will sand easier, and is easier to remove from unwanted areas. For bigger reccessed lines, or small joints, a gloss enamel varnish will provide a very good, and very hard filler, which can be sanded to a mirror gloss finish if needed.
Hope this helps.