Is this serti dial factory or custom-added?

[Wisher]

In looking for my Pepsi GMT II, I came across this GMT II root-beer X series with serti dial. I tried it on in person, but wanted a Pepsi. Now, though, I am thinking that this also would add variety to the collection, so it has been on my mind ever since. It's a nice combination of sports/dressy. It's actually a pretty stunning watch, especially seen in person, with an unexpected subdued-color combination, i.e., neutral tans and browns diffusing the gold, diamonds and rubies.

I was searching the Internet to find more info about the watch, especially because of the serti dial, but I can't find much info. It looks like they aren't common, although "rare" would be overstating. Serti are more common on Subs. I think a few GMT IIs also came with serti, so this is likely Rolex original. However, I came across several sites also with serti watches, saying "Comes with custom-added dial". To me "custom-added" means "aftermarket".

So, I was wondering if the experts know about the dial.

The pic is from a seller's website.


Thanks