Indexed 8-speed is early-mid 90s.
Early 9-speed will work.
I have a spare (98 I think) Chorus 9 spd mech that will do the job for you. It has no pulleys but is in fine condition. Can provide with new BBB pulleys at normal LBS price.
Quality early 9spd rear mechs are becoming quite hard to dig up.
£40 plus postage from Denmark.
Completed: 94 Stumpjumper w. M733; ; 92 Dave Yates 731 ; 97 Parkpre Pro-Elite ; Pace RC200 F6 ; Pace RC300; 82 Gios Super Record ; 97-8 De Rosa Giro D´Italia; ; Banani SPX Track bike ; 89 Alan/Mavic Cross Bike ; 05 Focus Cross Team ; 90 Look MI-80 all-Mavic ; 12 Focus Izalco Team/custom build ; 11 Focus Thunder Custom build
Projects : , Brouwer all-Mavic
Stripped : Pace RC303
Gone : GT Karakoram
Stayed in the family: Kuota Kharma, 04 Stumpjumper FSR
Ceased to be : Dynatech MT3, killed by corroded seatstays.