I can always count on you! You are correct.
States Rights as understood in 1860 concerned the ability of a citizen to enter any U.S. territory and not have his personal property rights violated. Most Southerners believed a territory had no right to make slavery illegal until it organized as a state. The territories were jointly held by all states, and therefore citizens from all states should enjoy the same rights and priviledges they had in their own states. Senator Douglas of Illinois believed the citizens of a territory could vote slavery up or down, and his name became anethema in the Southern states.
You will recall Fremont's campaign slogan in 1856: "Free Soil, Free Men, Fremont." Republicans also held that citizens of a territory could vote slavery up or down.
Prior to the 1860 election, this issue split the Democratic Party at its convention in Charleston SC.
That was States Rights, folks.