seems unlikely. the Union didn't recognize the legitimacy of Confederate secession (hence, you know, the war.) the Emancipation Proclamation only applied to rebel states, as an example. they may have had trouble collecting taxes, what with the bullets and all, but amending the tax code doesn't help that.

Someone actually expanded on it down the page as a way to punish deserters.

…which is exactly what the US criticizes Eritrea for doing with its citizenship based taxation! The only other country in the world to do this.