How to display the cut length of Pressure Pipe

These are specified in the catalog. Open the Content Catalog Editor:

• 2014: C:\Program Files\Autodesk\Autodesk AutoCAD Civil 3D 2014\Autodesk.Aec.Content.CatalogEditor.exe
• 2015/2016: C:\Program Files\Autodesk\AutoCAD 201X\C3D\Autodesk.Aec.Content.CatalogEditor.exe

And to label in Civil3D:
Add the following:
<[Cut Length(Uft|P3|RN|AP|GC|UN|Sn|OF)]>