It might make more sense for the future to use automatic numbering so you won't have the problem with missed references, however
Code:
Sub Macro1()
Dim oRng As Range
Dim sText As String
Selection.HomeKey wdStory
Selection.Find.ClearFormatting
With Selection.Find
Do While .Execute(findText:="\[[0-9]{1,}\]", _
MatchWildcards:=True, _
Wrap:=wdFindStop, _
Forward:=True) = True
Set oRng = Selection.Range
sText = sText & oRng.Text & Chr(32)
Loop
End With
ActiveDocument.Range.InsertAfter vbCr & sText
lbl_Exit:
Exit Sub
End Sub