I had an August 69 70 Barracuda (sequence number 100327) that I swear did not have beams in the doors--I wish I had pics to prove, but I don't.
I rememeber removing the driver's door and thinking how light it was. After removing the inner panel I saw no beams.
Years later I removed the doors from another early build 'Cuda (sequence 108632) and it had the beams.