
GUZZ's inquiry into the dial variations of his Patek Philippe Ref. 3940G highlights a common challenge for collectors: navigating the subtle, often undocumented, changes within a reference produced over decades. His experience underscores the importance of community knowledge and expert insight in authenticating and understanding the nuances that define these highly sought-after timepieces, especially when official records might not capture every production detail.

The Patek Philippe Reference 3940 is a perpetual calendar wristwatch that was introduced in 1985, succeeding the Reference 3450. It is notable for its relatively slim profile and the integration of a perpetual calendar complication in a refined case. This reference became a cornerstone of Patek Philippe's complicated watch offerings for nearly two decades, establishing a design language for subsequent perpetual calendar models. It represents a significant period in the brand's modern history of complicated timepieces.
The watch features a 36mm case, typically crafted from yellow gold, rose gold, white gold, or platinum. It houses the self-winding Caliber 240 Q movement, which is known for its micro-rotor construction, contributing to the movement's thinness and allowing for a slimmer case profile. The movement provides a power reserve of approximately 48 hours. The dial is protected by a sapphire crystal, often accompanied by an interchangeable solid case back and a sapphire display back.
Reference 3940 is highly regarded by collectors for its classic proportions and the enduring appeal of its perpetual calendar display, which includes day, date, month, leap year cycle, and moon phases. It was produced in several series, with subtle variations in dial layout and typography, making early series examples particularly sought after. The reference is considered a benchmark for perpetual calendar watches and remains a significant piece for those appreciating traditional horological complications.
Your Sigma belongs to first series and second series. Does the '9' in your watch connect? If it does, it belongs to series 1. Are you the first owner?
Usually when one has an official replacement dial, it will be of a later model. What I am afraid is it is a swap dial from dealer. For example, I have seen late Patek 570 (1969) watch with early 570 raised enamel signature dial (before 1966). Dealer insists that it is authentic and real. After some deep investigation, I found the picture of that exact watch before the dial was swapped. They share same archival extract. Then again, yours could be an early 3rd series and they decide to use the rem
Best, Patekova PS Beautiful watch!
Mine’s from 2004 and has the APRIOR inline with the minute markers, so it is indeed odd that yours does not. However, based on my humble opinion... (1) you sent it in to Patek for a service, and if it didn’t come back with any remarks, I think you’re good. If anybody tried to mess around with a 3940, I’m sure Philippe Stern himself would be up in arms; (2) this reference was in production for over 20 years and based on at least the examples that I’ve examined, the 1st 2nd 3rd series are not real
I've seen plenty just like yours. As Mike said, there's a lot over overlap between series. The only rule is there is no rule.
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