I recently purchased a 69 Camaro that has a 12 bolt rear end with disc brakes. I definitely don't think it's the original rear end, build dates are about 6 months apart. I know the rear disc was an option, but don't think it was an option for this car. Does anyone know if there is a way to identify the calipers or rotors by casting numbers?

 

Try a google search - GM #####

 

What are the numbers at the bottom of the caliper in the picture? What is the date code stamped on the axle housing?