Here's a photo of a blue front on left, and orange wing on right.
http://www.parrotchronicles.com/features/maypore/birds.jpg
Orange wings all pretty much look the same, to a lesser or greater degree. Blue fronts however vary widely in size and colorations.... from no blue coloration at all to a large amount of blue... and from very little to no yellow to a lot of yellow!
As mentioned, their beaks are also differently colored.... blue fronts having black beaks and orange wings having two toned beaks. Blue fronts may also have more coloration on the wings.
Here is a video of two young orange wings and a blue front in the same container.
[ame="https://www.youtube.com/watch?v=RzdyReyCFVY"]Shady Wings Blue fronted Amazons Orange winged Amazon Umbrellas - YouTube[/ame]
A little more information about the two species.....
AmazonParrots
Orange wings are amazing pets! I kind of prefer them to the blue fronts anyway.

If Alfie has the two toned beak, then Alfie is an OW!
Hybrids between the two species have occurred, due to the confusion.... here is one such hybrid. Body of a blue front but the beak leans more towards the orange wing side. Head coloration is mostly orange wing, cheeks appear more blue front though.
https://www.flickr.com/photos/mfids/7881733726/