That is a great period photo!
The Wally Byam's Caravan Sticker was often used on caravans, but was also used by club members who were not on any caravans in the early 1960's. It was replaced by the typical round WBCCI sticker in approximately 1963
The Airstream in this photo appears to be a 1963
24' Tradewind built in California. The WBCCI #7942 would have been first assigned in late 1962
which would be reasonable for an early 1963
Airstream that could have been built in late 1962
. Based upon the age of the car, I believe the photo is from around this time period.
The first assignees for #7942 were Charles and Phyllis Lent of Vancouver Washington. They are listed for this number in the 1964
(membership as of 1963) through 1975 Membership Directories, but are not listed as having participated on any caravans.