Their web site says:
"The same master gunsmiths responsible for the quality and performance of Performance Center handguns will apply their expertise to upgrade, enhance and refurbish your new or existing revolvers and pistols. Because these services and packages are through Smith & Wesson, you can be assured of professional service and a high quality result. Express Services available for unaltered guns from 1990 and newer.
To discuss Smith & Wesson Performance Center Services call 1-800-331-0852. Please have your serial number available when calling for information."
I suggest checking directly with S&W.