From Team Fortress Wiki
Several turrets were designed and created during Team Fortress 2's development, although all were ultimately scrapped before the final release. These unused turrets appear to be the descendants of the spawn room turrets from Team Fortress Classic.
- The miniturret and turret have designs that don't match the current style of TF2, as they were placeholders recycled from Half-Life, another Valve game.
- The top of each turret has the word "DANGER" written on it.
- A turret more in line with TF2's current art style was created, but all that remains of it is a texture sheet.
- The TFC turret files can be found in the model list of the Source Filmmaker. It can be used in the program as an editable model and it can only be placed through this way.