The add-a-ball version of this game is Williams' 1967 'Blast Off'. The promotional photos for both 'Apollo' and 'Blast Off' show the playfield posts were yellow in color. All of the playfields pictured here have red posts. We presume they came from the factory that way but we don't know when in production a change of color would have occurred. Manufacturer data for Apollo: Quantity produced for USA/Canada: 1812* Quantity produced for export: 1288* Total quantity produced: 3100* Price to Distributor: $375.00 *These quantities may be sales estimates.