Google Merchant Center has introduced a new ‘build to order’ value for the availability attribute, specifically for vehicle listings. This update gives dealers and sellers a better way to represent cars that aren’t immediately available but can be customized and ordered directly by the customer.

The ‘build to order’ value fits brands and situations where vehicles are made to the buyer’s specifications, such as Tesla or Rivian. These vehicles are not off-the-lot purchases and now Google provides a dedicated option to reflect this unique buying process.
Sellers must update both their structured data and data feeds to use the new value.
It is also mandatory that these listings have the condition attribute set to ‘new’. Products marked as ‘used’ will not be approved.
This update was discovered by Emmanuel Flossie.