[FirstOwner69]

My '69 3/4 ton has never had the braces. Based on my observations, I believe they started using then later... most likely 1971.

Here's a picture of some parts I grabbed at the local junkyard. The length of the channel shaped braces varied depending if the truck was a 1/2 or 3/4 ton. If I remember the longer one was from a 3/4 ton.