Sorry, I forgot about your "." before the tab. Try one of these. At this, I'm not sure either is very efficient, but both seem to work with your examples and with paragraphs within the enumerated items.
HTML Code:
Sub ScratchMacroII()
'A basic Word macro coded by Greg Maxey
Dim oPar As Word.Paragraph
Dim oRng As Word.Range
For Each oPar In ActiveDocument.Range.Paragraphs
Set oRng = oPar.Range
oRng.Collapse wdCollapseStart
oRng.MoveEndUntil Cset:=vbTab, Count:=wdForward
If oRng.InRange(oPar.Range) And oRng.Start <> oRng.End And oRng.Characters.Last = "." Then
Set oRng = oPar.Range.Words(1)
ActiveDocument.Fields.Add oRng, wdFieldSequence, "Numbered", False
End If
Next oPar
End Sub
Sub ScratchMacroI()
'A basic Word macro coded by Greg Maxey
Dim oPar As Word.Paragraph
Dim oRng As Word.Range
For Each oPar In ActiveDocument.Range.Paragraphs
If Not oPar.Range.Words(1) Like vbCr Then
If oPar.Range.Words.Count > 2 Then
If oPar.Range.Words(2) = "." And oPar.Range.Words(3) = vbTab Then
Set oRng = oPar.Range.Words(1)
ActiveDocument.Fields.Add oRng, wdFieldSequence, "Numbered", False
End If
End If
End If
Next oPar
End Sub