Does it make noise in all environments? Not all the old instruments need the upgrade. I have a '76 medium scale guitar and a '77 long scale 12 string, both Series 1. Neither has had the upgrade. In most situations they do not make noise (unless, of course, I want them to). Sonicus, a member of this site, has an early Series 1 bass that made noise in the studio where he bought it (near lots of RF interference), but is relatively silent in my studio.
Bill, tgo