Jenever,
First of all, welcome and I hope you enjoy your watch.
Second of all, NEVER file a paypal dispute without talking to the seller first. This should only be used as a last resort (if even then) and only if it is an absolute scam. Remember you are purchasing a counterfeit item and must assume some risk on your part.
This only leads to sellers accounts being frozen and, in turn, them not accepting paypal as a method of payment. It's also kind of hard for the seller to defend themselves trying to explain that they hid a XXXXXXXXX so that customs wouldn't seize the watch.
OK...Scolding over...live and learn...and enjoy that watch.
EDIT add - I knew some of our members wouldn't be too kind to you, but you have to understand why. It's stuff like this that puts our hobby at risk.