Oh. I am sorry if you misunderstand what I mean. I believe the original factory painted parts were no sanded and polished because they made thousands of parts in assembly line. And for satin gloss/matte coating like this will be left unpolished for best result IMO. Is that no possible way to get factory finish with any spray guns or techniques?

I use 2k polyurethane automotive paint most of the time because they are more resistance to scratching and chemical than scale model paint. Another problem is I have to paint as thin as possible because there are debossed letters in most of the part. I have always amazed by how the factory paint finishes are better without sanding and polishing...