|It matters little Whether is it is a primary or secondary drive as long as the BIOS boot order points to it.|
The label doesn't matter either. You could make the label "Mickey Mouse" for all the difference it makes.
However, drive letters do matter. Drive letters are allocated by Windows each and every time it boots so you need to make sure that the cloned drive is in the same boot order as the original so it gets the same drive letter as the original. What is says in the drive label is irrelevant.