Hi all! I just bought a Linhof 4x5 monorail and wondered if anyone could help identify the exact model so I can look for a manual? On top of the metal part of the rear standard, under the Linhof badge, it says 'Color' and then on the part of the rear standard that holds the ground glass it says DBP. On the bottom of the rear standard near where it clamps to the rail, it has the serial number 5137. Thanks in anticipation!