Hi Longboarder. I looked up James Suckling's reviews for the 1997 Rosso and Brunello and found that SO2 was not mentioned in either. In fact, they scored 90 and 97 points, respectively.
This leads me to believe that there was a single or small run of bottles that may have received a larger than usual dose of SO2 prior to bottling.
Lucky you for getting that bottle. I hope that your eyes and olfactory epithelium have recovered.