I think there is another thread here re 5940, although a bit old. www.watchprosite.com I have a 3940, and the 240Q movement is a workhorse and very reliable. Not to mention it’s an absolute beauty, and I find some new detail every time I check with a loupe. As Patrick noted, despite being hi
5140’s official diameter was 37. 2mm actually 😂 But as other folks have mentioned, it does wear larger than it seems, lug-to-lug length is 45.7mm. If you’re looking for white metal, a plus point to consider is 5140Ps came with exhibition back unlike the 3940P predecessor, which were all fitted with
Since both have lug width 20mm, technically it should fit in the space, but may not “fit” the case as the GMT has the beefier maxi case in 40mm and the Datejust is a slimmer 36mm. You may end up with some parts sticking out instead of sitting flush.
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