Tony, I don't have as much experience with Angel Wing as others, but I'll pop in my 2 cents, for what it's worth...
Io went through it, an it was much more turned out than that, but I am not convinced it wasn't caused by her sleeping with her left side wedged against the brooder... I dunno why, but she had a certain spot she always insisted on sleeping, even if she had to squeeze into it, lol... I wrapped it for a few days and it was fine...
But, I had a grey that had some issues when her flight feathers started coming in and it looked almost exactly like the pics of Casey... I don't think it was Angel Wing, but just that the feathers came in so quick, thick and heavy that her wing muscles couldn't keep up to the new weight yet... I just helped her tuck them in properly when she was sitting and eventually her muscles caught up to the heavier wings...
I would keep an eye on it though, and wrap it if it gets worse... a few days is all it would need when caught early... but I'd see what others say... hope this helps...