Just looking over the collection (paying particular attention to redeco lines (like Universe, Classics, BotCon, etc), and conferring with Demonac, there appears to be one Megatron toy that has been used as an Autobot - T-Wrecks (using BW Megatron mould).
It is probably the only one that uses a distinctly "Megatron" mould for an Autobot... compared to the dozens of Decepticons using distinctly Optimus moulds.


So does this mean that the moral of the story from Hasbro & TakaraTomy, is that naughty/evil/criminal people never redeem themselves and become good... so there is no point in trying to turn over a new leaf and do something good?