A release candidate vehicle is almost certainly what other manufacturers might call a production validation (PV) vehicle. Motor vehicles move through concept and design durability prototypes during the development process, with increasingly production intent design parts along the way, even if the parts are made by prototype processes. The final step is a PV vehicle, put together with parts that are not only production intent designs, but made by production processes (cast rather than CNC-machined, etc.), and assembled on a production line rather than by R&D mechanics. Typical PV runs are between 30 and 500 vehicles (the larger number for vehicles that will be made in the hundreds of thousands of units), and usually there's about 6 months or so between the PV build and start of production (SOP). PV vehicles are used for final durability and field testing, but also for many other purposes, such as PR, photography, advertising, service procedure development, etc.