Swatch Group service in the US has some nice people, but what seem like some very antiquated processes.
I had trouble and delays with a Breguet that I returned because they typi’d my email address wrong in one of the two ! places they had put it
and when I asked for the original parts they replaced that was clearly a non-standard request, which threw them for a few loops
I was once told that Roland Murphy – RGM watches – was once in the business of aftermarket modifications to give Leman cases display backs.
But unless they planned for a display back, Blancpain puts the serial number where the back crystal would go!
In the MYC variant, they put the SN on the weight
Before you request a display back you might want to make sure the SN is retained somewhere suitable