speedometer adapter
 

In box # 92 of my build sheet it reads 21-red-c. My car came with 4.10 gears,but the original owner said that he does not remember any speedometer adapter on the transmission.I thought that all cars with the 4.10 gears came with the adapters? Is there any other way to tell if my car came with this? If so,what would be the correct part# for it?