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Airstream hasn't been known for its consistency with model name usage since about 1968
. Since 1968
the meaning of a particular model name had a tendency to change from year to year. Prior to 1968
, the model name (Safari, Overlander, Ambassador, etc.) referred to the length of the trailer while Land Yacht applied to the standard equipped model and International referred to a upgrade option that featured a variety of components that did change from year to year. About the only way to determine just what equipment was included in a particular year's trailer of a given model is through the sales literature as even when the model names were more consistent in the 1950s and 1960s, the standard (Land Yacht) equipment level varied to a degree and the components included in the International package varied from year to year.
Good luck with your search!