No, but if they'd freed their slaves, or even put freedom on the calendar, Britain and France would have recognized them, broken the blockade and they would have gained their independence.
But the problem was that the reason they wanted independence was to protect slavery, so independence without slavery was irrelevant. The CSA Congress debated the issue of whether to free even the slave soldiers they were recruiting as late as well into 1865, when most opposed the idea despite the utter peril of the times.
Also, of course, had they freed their slaves they would have had no terribly important reason to leave the Union in the first place.
None of that negates the fact that Lincoln was willing to allow the institution of slavery to continue in the states where it already existed and only went to war to retain them in the union. I’m also not sure Britain and France would have recognized them without greater military success on the part of the Confederacy. They were both colonial powers practicing their own forms of de facto slavery on a national scale.