In this case, it's a Ulysse Nardin, WW2 era.
Assuming the shipper knows what they are doing, Marine chronometers are shipped 'corked'. That is, the balance is prevented from moving during shipment. The chronometer is also typically shipped with a small amount of power wind, so that it can be started with the movement out of its brass tub.
Corking the instrument prevents the balance from moving too far to either side of the swing during shipment, which can damage the chronometer.
See here for the uncorking process:
https://www.instagram.com/p/BEjWpTDmeJw ... sicwatchdc
This free the balance up and the instrument is ready to run. You can either give the balance a gentle finger flick or rock the entire movement side to side in circular motion that mimics that of the balance wheel to get it started.