No. When you publish a service you declare it as being generally available, without constraints on the way in which it is used. For example you cannot limit other bundles to call methods in a particular order, or require them to use synchronization, or to always call from a particular thread. Therefore you must assume that you will be called from any thread, without synchronization, etc.
If the internal state of your service implementation is fragile and requires synchronization, then it is your responsibility to do it inside your implementation. You cannot force this work onto somebody else.