I had the pleasure to try both, red gold and platin... i love the weight of platin, but i think the rose gold could be my only dress watch. I have too many sportwatches, but not really a dress watch.
...that's my hand in the photo holding the watch, and I remember it was quite heavy. I have a shot of the back but it isn't great so I might not be able to see the markings for the metal, if any. I will take a look and see what I can see.
...I'm sure he has more than one personal watch...perhaps the prototype was steel. Either way, he was wearing the platinum version when we met last year in April.