You can’t answer that in a vacuum, because the effect depends entirely on the circumstances. If you say “bob has a conviction for whatever”, then obviously the lack of any conviction any more will be raised. The assessment as to whether a statement is true or not depends entirely on what was said. Whether what was said amounted to slander or libel depends on what was said. If it related to bob being a convict or a felon or a person with a criminal record, then the status of his record will be relevant.
You are changing the question. The question isn’t can the wording of the statement make a difference between libel and not libel. The question is does an expungement change the status of the person so that an otherwise true statement would now be false because the record of it was erased. Arguing whether an arbitrary time period makes one not a thief is not relevant to the question. I can’t see how using the word “thief” instead of “someone who stole” would have any LEGAL difference. Like I said I picked that example at random. Pick any other crime if you wish.
It DEPENDS on the particular statement made and being considered. It doesn’t change any “status of the person” which is irrelevant.
Is the statement that was made true? That is the question. Whether an expunged conviction is relevant depends on what statement was made. Statements asserting that Bob has a conviction=possibly relevant. Statements that something that you witnessed happened=probably not relevant (unless the legislation says so). The administrative removal of a record cannot change events. If they happened, they happened. If you make a factual statement “i was there, this is what I saw” ok, using descriptive terms that mean different things to different people, you have to prove that it’s true, which you may have problems doing.
For those who are curious about the question, the Volokh blog cite really goes into detail about the (at the time) lower court case and discusses how the 2nd would likely rule. Par for the course for his excellent blog, The Volokh Conspiracy. It’s one I really recommend for people who are curious about current developments in the law. The post also links within it to the NJ Supreme court case I mentioned.