We gave the Vic personal plates back in 1991 when we moved to QLD, however a family member who has had their personal plates since the early 80's is still paying a yearly fee I believe.
I think you'll find what keegs said is correct, unless you can see otherwise on the Vicroads web site, I know Mario? with GTR700 said he wasn't going to ever give his plates back when the rego came off "GTR700" as technically he never owned the plates, just paid a once off to get them, plus a yearly fee, plus rego costs.