From my understanding, no, however I could be wrong. It’s as follows:
All solid gold is yellow. Gold is then mixed with other metals to create an alloy (14k, 18k, etc). Historically it was mixed with things like bronze to keep, or even enhance, it’s yellow coloring. Rose gold is mixed with copper to achieve that reddish/brown look. And finally white gold is mixed with palladium or platinum and is a grayish-white in its final form (while still retaining its natural yellow undertones in varying degrees depending on its formula).
So, “white” gold does actually exist — however, the majority of used in jewelry settings is then plated with rhodium (as stated above) for that ultra bright flawless look.
Rolex does not plate their white gold in rhodium. Instead, they have a proprietary formula for creating white gold that has a beautiful solid white, cold-grayish finish, with beautiful yellow undertones.
THIS cannot be duplicated without finding/formulating a similar-colored white gold alloy and having a custom case, bracelet, etc made up. But at that cost, you might as well buy a gen.
This is my understanding at least. I researched the topic heavily after falling in love with the Submariner “Smurf”, but not loving the difference of finish in the stainless rep (nor having a spare $50k for the gen hahah).