Dean's collar alternates from up to half-up while he's talking to Bobby before being zapped to the green room.
The chapel where the main action occurs (in the opening, and with Lilith) has an altar emblazoned with IHS, the Ignation order of the Society of Jesus (aka Jesuits). Jesuits work with nuns, but only formally admitted nuns into their order in 2014. So, the idea of a Jesuit overseeing a convent of nuns doesn't make sense as of 2009 (when Season 4 was airing).
The newspaper with the article on the priest killing the nuns is dated for "Friday, October 16, 1972." However October 16th, 1972 was a Monday, which incidentally means that the 13th was a Friday, and thus would have made for a more thematically appropriate date on the article which would have actually been accurate.