This would be quite difficult, the best you can do is make it more shiny I assume. But you will have to have a whole new dial made to achieve the sunburst effect, it seems as though ZF essentially placed paint over the dial to achieve the colour.
Its incredibly difficult but I have an idea of how to do it. But it will require many many ZF dials and a LOT of trial and error.
Sunburst dials are usually cut in a sunburst way, and then anodised to give them the colour.
On the 15202, the tapisserie gives the dial the same effect as cutting it like a sunburst dial.
Let's say that ZF started off with a dial that was cut the same way as the gen, and painted it to achieve the colour. What an insane modder could do who has alot of time and money on their hands, is to remove hour markers and AP logo, then the paint using random thinners and paint removers, hoping they can remove the dial paint. Once thats done, they can buy an anodising set up, and basically sacrifice a few dials to figure out how long one needs to be anodised. This can vary alot. Its exactly why AP dials are rejected in manufacturing.
Then the hardest part is placing the markers and logo back, and figuring out a way to have the Audemars Piguet logo printed back on the dial in white.
This is something that honestly ZF could do, cause the tapisserie they have on their dials, mean that they probably have a similar machinery set up to what AP has as shown in this video:
https://www.youtube.com/watch?v=K0uW37FnCLM
but it would cost a huge amount of time, and a whole lot of MOOHLAH