The Swift archive does not go back to 2004,but the 2006 model is shown as having an inboard pump. I cannot see the point in having an external pump as well, so if the 2004 model had an inboard one, I can only assume that at some point it was replaced by the Whale model. You should be able to check by following the pipe inside from the inlet to see if there is a pump there, but I doubt it.
From personal experience of inboard pumps they are very noisy and many people did replace them, so that or the pump failing, might explain the possible change.