From what I know of serialization,
Any changes to the fields will change the serialVersionUID, and so make serialization impossible from "old" instances to "new", unless ...
You explicitly set the serialVersionUID, as you did, which effectively disables this check. By the way, you don't have to set it to such a cryptic number, unless you're trying to match it with a version of the class that didn't explicitly set the value. Normally, you can just set it to 0 or 1 or whatever. Not everyone knows that.
So, now we can serialize between different versions of the code:
Any member data that is present in the class available to the deserializer, but not in the serialized object will be set to a default value. (null, 0, or false)
Any values present in the serialized object, but not in the member data will be discarded.
So, I think that answers your question, but I agree with Paul that
you should just run it through some tests. After all, my memory could be faulty, or serialization might have changed in the 14 years since I last looked into in that level of detail. Incidentally, you might look into the weird private methods readObject() and writeObject(). They can be useful for converting between different object versions. I'm not sure if they could help you in this case though.