They do wear the helmet before entering the temple/ship you can see it in some of the SDCC footage leaked images.
The scenes with a boat supposed to be shot in spain never happened.
The ampule room is not on Earth.
The dicovery on Earth is some sort of text, transmission, map... Not a giant room housing ALIEN urns and a massive bust.
From EMPIRE.
"The crew of the Prometheus (the ship's name designed to echo the Greek myth) follow a perplexing message to a planet that will open their eyes and their chests to a new alien race."
If the Ampule room was found on Earth the journalist would have not asked what it was to Scott at the end of the article.
He would have just said the discovery of the Ampule room on Earth ....