https://www.rugbyleagueproject.org/seasons/nswrfl-1983/round-21/st-george-dragons-vs-easts/summary.html
There is a number 17 playing for St.George seen at 0.53, 1.05, 1.09. & a 15 at 1.25, neither are Graeme Wynn, the reserve used. At 1.20, it looks like Wynn playing in a jersey ending in 8.
At 1.21 there is a 21 playing for Easts
https://www.youtube.com/watch?v=exf75FqAnqI
Sorry I couldn't be of any more help, but a Dragons or Roosters supporter may be able to help.