The scene in which you can see the shield is after Iron Man returns from Afghanistan after fighting with the Mark III red/gold armor for the very first time. Right after he fights the two F-22 fighter jets, it shows him back in his lab trying to remove his armor but having trouble. Right as Pepper Potts walks down into his lab and asks him "what is he doing?", the shield can be seen sitting on one of his tables behind him in the lower left corner. This happens around 1 hour and 30 minutes into the movie. Make sure to account for trailers if you're going in. We confirmed it at a 6:40PM showing and the scene played at around ~8:18PM. Here is a very low quality photo just for reference. It looks much better in the movie.
The shield is actually red, white, and blue, although you can't see the red in the photo. But if you see the scene in the theater, the shield is actually there and very identifiable. It looks like it is half-constructed and being built by Tony Stark, but you can definitely see the unique star. It is a round shield with circular red, white, and blue stripes.
