The standard or option status varied with model and year, but Surge Guard panels began as included factory equipment on some models around 2004. Interestingly, it was a listed option in the '04 Monterey brochure but not some higher-end models; then it was standard on '05 Montys, but not necessarily listed as such on other '05's.
Of course what was in brochures as intended was not necessarily what came to be as a model year proceeded.
Joel