A man who worked for the aquarium identified it as semipalmated. I don't know much about shorebird IDs, so if you (or anyone) wants to prove him wrong, go ahead. I'm not sure if the aquarium claims to have western.
You're right that the bill does look a bit long. The aquarium doesn't list either species on its website. Perhaps it is a western- I don't remember seeing western when flipping through the ID guides, but that was nearly three months ago.