You won't need to cut & paste anything. All you'll need to do is fold each front/back pair down the middle then laminate. You can even use the table tools to change the text direction for one side of the label in the mailmerge main document, if you like. Much less work and far more reliable than messing around with front & back mailmerges, remembering which way up & around to feed the first print into the printer, having to worry about whether the front & back align properly when printed, etc.
But, if you're absolutely wedded to using a macro:
Code:
Sub MailMergeToDoc()
Application.ScreenUpdating = False
Dim Tbl As Table, Rng As Range, c As Long
ActiveDocument.MailMerge.Execute
For Each Tbl In ActiveDocument.Tables
With Tbl
For c = .Columns.Count - 1 To 1 Step -1
.Columns.Add
Set Rng = .Columns(c).Cells(1).Range
Rng.End = Rng.End - 1
.Columns.Last.Cells(1).Range.FormattedText = Rng.FormattedText
.Columns(c).Delete
Next
End With
Next
Application.ScreenUpdating = True
End Sub