Did all 68 SS's come with the reinforcement braces on the rear suspension, or was it a dealer add on at the time?

As far as I've heard, and I'm really not sure about it, is that the braces come with the F41 suspension option and on all 4 speeds.

Tim.

I picked up one of those restoration kits from GM for a 1969 Chevelle. Now, I don't know if the 68 is the same, but according to this, the only cars that got the reinforcement was the big block.

I'm editing to add a question. I'm new to Chevelles. My 15-year old and I just bought a 69 Chevelle that we are restoring.

On the subject of the frame reinforcement, is there a part number for the reinforcement? (BTW, I did a search and did not find this info.)

Thanks!