I don't buy this. I'll point to Iron Man #150 and the What If? issue that changed it as evidence.
In IM150, Iron Man and Doom end up trapped back in Arthurian times. In the end, Doom proposes they work together to build a time machine that will take them back to the present.
"How do I know I can trust you?" asks Iron Man.
"Because, Avenger- I give you my word," Doom replies.
And they work together, build the time machine and return to the present.
But in an issue of What If? that starts at that point, the key difference is Doom's reply: "Because, Avenger- you have no choice." So when teh time comes, he betrays Iron Man and leaves him in the past at Camelot. The key difference is that he keeps his word, which is an enomously lawful trait (IMHO).