I recently purchased a 26' 1968 AS international Overlander. It is in pretty good condition with all the original equipment. The title that came with the trail indicates that it is a 26’ 1964 international Overlander. However upon further investigation I believe the trailer is a 26’ 1968 international Overlander. My trailer does not have the door-in-a-door feature nor the louvered jalousie windows adjacent to the door. More interesting the serial number on the stamped on the Airstream data plate seems to be missing some letters/digits. Came someone help me with this mystery. There are some number stamped above what I believe to be the serial number, but I have not been able to find any reference to these numbers, anybody have any ideas?