Patek has been clamping down on these so called “deliveries”. If the watch is in the realm of a MR then I believe it has to be picked up in person. They will want an in person demonstration of how the watch works and make sure you understand it as well. As for the “regular” references like Calatrava, Annual Calendars, etc. I’m sure most are shipped to buyers if they cannot make an in person pick-up.
Having said that, don’t think this watch 5531 was delivered to buyer unless Patek made an exception which in this case may have due to Covid19. What I’m wondering is what happened to the watch? Was it undeliverable or did the buyer decide not to take delivery and was subsequently sold at auction.