Wrong, the Confederate Constitution forbid international slave trade from the get go.
Section 9
Clause 1: The importation of negroes of the African race from any foreign country other than the slaveholding States or Territories of the United States of America, is hereby forbidden; and Congress is required to pass such laws as shall effectually prevent the same.
Clause 2: Congress shall also have power to prohibit the introduction of slaves from any State not a member of, or Territory not belonging to, this Confederacy.
http://www.evervigilant.net/documents/confederate.html
Wrong, the Confederate Constitution forbid nternational slave trade from the get go. Let's look at clause 9 again:
"Clause 1: The importation of negroes of the African race from any foreign country other than the slaveholding States or Territories of the United States of America, is hereby forbidden; and Congress is required to pass such laws as shall effectually prevent the same."
Correct me if I'm wrong, but the confederacy considered itself a sovereign nation, so any imports would qualify as an international import. And clause 9 specifically protected international imports from sections of the United States.