I can kind of under him not recognizing her face, but her clothes?
The sweater she is wearing when she is taking pictures at the dock is the same one she wore when he carried her to the car when they were eloping. Also, the boots!
Don't get me wrong, I LOVE this movie and have seen it more times than I can remember. I think most of her wardrobe is the same throughout for both personas.
Just saying he's not very observant for an architect, someone who is supose to have an eye for detail. Makes me laugh every time.