This part of the posting, which looks to fill a graphic artist position at the studios, is what caught my eye:
"[Candidate must] research items, timelines, events, people, etc. relevant to the period being covered in film to provide a high level of detail and authenticity."
So obviously, this is for 1906, unless Pixar happens to be working on another film with historical themes, which is highly unlikely. The Civil War-era parts of John Carter of Mars may be a possibility, although again not likely considering that that film's script is still in development.
(Please note that the poster displayed is only a mock-up. I based it on the cover of the novel by James Dalessandro.)