4:30-4:40 minutes. When Trinity and the agent jump over the gap between the buildings the billboard of 'Guns and Ammo' has the gun picture pointing down. As the group of cops land, the gun on the billboard is aimed up.
The gun is really a cardboard projection on the billboard. It's a 3D billboard. So the way the gun "faces" changes when you view the billboard from a different angle. The two scenes that you talk about are showing the gun at almost opposite angles.