Kind of, elements of what would become modern day Fundamentalist Christianity had been building since the Great Awakenings of the 18th century and carried through the Civil War. Four common threads tie modern fundamentalism together, Evangelism, that is Conversion-centric, Dispensationalism, a premillenial worldview that put the world in line for a new Godly arrival, the principle of Biblical Inerrancy, and rejection of modernism and biblical higher criticism. Evangelism has its roots in the United Kingdom and US in the 1700's and Dispensationalism in the 1830's. While i'm not sure of any specific root that comes directly from the Civil War, the War ended the ongoing debate over the Curse of Ham narrative employed by slave owners to justify their slavery. It is possible wherever you heard this from is discussing how Biblical Criticism was in high development in the 1850's and 1860's and many portions of the Bible were assaulted as mystical or untrue, prompting the Fundamentalist Biblical Innerrant thought.

If you're really interested, I highly recommend Mark Noll's Americas God

Sort of. The course of events that embroiled the mid-century western world, including the American Civil War, gave rise to the conditions under which fundamentalism arose in the late 19th and early 20th century. But I wouldn’t place pro-slavery, conservative theologians necessarily as proto-fundamentalists. Certainly, some shrewd proslavery theologians espied German higher criticism in the mix with liberal Protestantism that supported abolitionism, and denounced it. But at the same time, southern theology—and more importantly, social faith practices—embodied a liberalism toward the world that later fundamentalists rejected.

Should you look to the Civil War for the “ideological origins of modern fundamentalist Christianity,” you might look to larger social, cultural, technological, and economic made possible by northern victory in the Civil War. The triumph of free markets, free labor, and scientific/technological enthusiasm created the conditions of scientific modernism that fundamentalists at the turn of the 20th century defined themselves against (ironically, using scientific methods.)

What I know comes from reading these, among others:

Beth Barton Schweiger, The Gospel Working Up: Progress and the Pulpit in Nineteenth-Century Virginia (1999)

Molly Oshatz, Slavery and Sin: The Fight against Slavery and the Rise of Liberal Protestantism (2011)

Sydney E. Ahlstrom, A Religious History of the American People (2004)

George Marsden, Fundamentalism and American Culture (2006)