This actually is not a bad thing so don't worry. I don't know if you remember that before James McCullen was cast as Destro ord went out that David Murray was cast as Destro first. Well it looks like both of them are in the New G.I. Joe movie and Both of them are going to play Destro! Here is the explination Thanks to hisstank.com:
Hiss Tank.com has just received some new Casting Information from our agent 001 reporting in from the European Cinema Expo. It would seem that David Murray the original actor picked to play James McCullen AKA Destro is still indeed set to play Destro in the G.I. Joe Movie "Rise Of Cobra".
David Murray will play James McCullen The 1st (The Original Arms Dealer)! He will play a huge part in the telling of the Destro Clan back story and how the "Family" came to don the Menacing Mask.
So thats cool a little back story to the origion of Destro and how he came to sport the shiny silver mask of death!