Good news: by and large, these indexed shifters essentially never (as in like 99.99999999% of the time) need an servicing or lubrication. It's pretty remarkable to dig up mid- and low-end SIS shifters from the late-'80s and early-'90s, put them on a bike, and have them work just fine. If the bike is in remotely decent shape, which it sounds like it is, you could clean the RD jockey pulleys or just leave them, tune the RD, and ride for a million more miles.