But the ref 3615 is a bit more rare, since it's unique. Monopusher chronograph, perpetual calendar and minute repeater. I believe it is in their museum. Than there is PP No. 198.393 which is a perpetual calendar with split-second chronograph sold in 1938 (source: Huber and Banbery, this could be a 2571 though...).
Regards,
Joram
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