VIN number on plate by door . . .
The four digit number stamped into the Airstream plate next to the door is your VIN (Vehicle Identification Number), the number which is used on the certificate of title. There never was a trailer serial number or VIN stamped into the frames in 1948
, so the plate riveted (occasionally screwed) onto the trailer is it. Any number stamped into the frame would have been the frame manufacturer's number, not Airstream's number, so don't use it if you ever find a number stamped into the frame. Hope this helps.
Fred Coldwell, WBCCI #1510, AIR #2675
Denver, Colorado - WBCCI Unit 24
Airstream Life "Old Aluminum"
Airstream Life "From the Archives"