Yep, Lava Boss nailed it!

I think another way Destro has a "Code Of Honor" is that he doesn't try to purposely target innocent civilians. I believe that was the original idea that hasbro had when creating Destro, but it doesn't work out, because in the cartoon and comic book (the Marvel Series) they wanted to shy away from Cobra killing innocent civilians. The Devils Due comic series is grittier and lets you see innocent people getting killed, but it does little to support my theory, because Destro was selling hardward to Wingfield and at least "by Proxy" was responsible for the deaths of innocents.

In my JoeVerse, Cobra Commander is like the crazed terrorist, wanting to unleash massive destruction, but Destro wants it to focus only on the parties it need to.

Lava Took The Words I Wish I Had Out Of My Mouth.

I agree in that Destro does seem to have a code when it comes to compassion for innocent, he doesn't want needless casualties if it can be swayed away from. That doesn't necessarily mean that he wouldn't shoot an innocent man if it was good for business. It really all comes back to greed and the all mighty dollar: Destro is all business. He's going to make that money the best way he knows how. He respects anyone who will put up an honorable fight or at least fight for what they beleive in but he's all about the money in the long run.