Ichabod is surprised that there are people allowed to carry guns in "militias," and Abbie comments that it's the 2nd amendment at work. Ichabod then admits that there was considerable concern on that notion although, according to the storyline, Ichabod was buried in the cave long before the Constitution was drafted, and that was some time before the Bill of Rights, including the 2nd amendment, was added in. Therefore, Ichabod could not have known what was going on in regards to how people felt about any of the bill of rights.
Ichabod bemoans that his mobile phone company keeps sending him messages to add updates for a fee, saying that this is an abuse of capitalism. The word capitalism did not exist during Ichabod's time, not coming into common use until the middle of the 1800s during the Industrial Revolution.