So as the title said VoxelSniper doesn't seem to copy them over like in the picture that i have attached, WorldEdit copy to the left and my VoxelSniper with no air copy to the right. You can see the skulls are not the same.

I am using 1.6.2 Build #244 so i know its outdated cause i'm on a Pixelmon server. So its what i have to use atm but if this is still an issue with latest versions or no one has reported it. I'm here to let every one know. With other issues having Meta-data being an issue. Looks like that is what VoxelSniper hasn't added.

VoxelSniper doesn't save any sign, skull or such metadata while copying, you're better off using WorldEdit until that's implemented.

Oh, hope it does one day.