866 and 863 are the same base plate right? The only difference is a module for the moon phase right? And that would only be seen from the other side of the movement.
Seems like time to get an extract.
If it is an 866...
1) a 866 baseplate got mixed into the 863 parts bin and you have a factory mis marked movement.
2) the original movement got trashed and someone had a spare 866 movement pulled the moon phase off of it and swapped it in which would be weird as this would be a reduction in value for the parts at hand.
3)during a service the base plate got swapped with another watch in for service at the same time.
4) the watch is a really good fake. Do those subdials seem correct to everyone? The seem too inset in the pictures.
Click to expand...