At a minimum, you have raised a valid question. There may or may not have been fraud. That would require finding more facts. But a notary could not have witnessed all the signatures in 9/10 and already have a stamp that expires 8/15. Assuming the self proving affidavit is what was notarized, you certainly could challenge the affidavit.
Remember, however, that a will does not need to be notarized in Georgia. If it was signed and witnessed properly in 9/10, and the affidavit was done later, that does not invalidate the will. It just is subject to different standards for proof to probate. If the will is being probated and you are an heir, I would raise the issue with the probate court where the will is filed.
This answer is for general purposes only, and it does not create an attorney-client relationship.