Alright, I am going to give you all a bit of disappointing information.
I will try to find the Forum Post (Runescape Forums), but a Mod on there said they are not offering to reinstate old bans, just bans you are getting at the present time. So if you had a main banned last year or 2 years ago (or however long ago), you will not be offered this opportunity... for now.
So, they might start offering to reinstate older bans, but as of right now, they are not.