Furthermore, these two scenes, that emphasize the physical similarity between Tony and Morgan Stark, are a perfect example of why the adoption retcon makes no sense.
This one comes from Iron-Man # 286.
And this one comes from the 2009 War Machine series.
They show that, if Rhodey, who knows Tony better than anyone, could confuse the two, it’s because the family resemblance they share is huge. This is especially emphasized in the scene in the War Machine book, where Rhodey is talking to Morgan, showing that Tony and his cousin even have similarly sounding voices.