It looks like several 69 z28's with build dates from at least 10D through 11A received the shorter length rear rally stripes. Mine having the 10D build date. I guess no one can say all Los built z28's built between those build dates had the shorter stripes, but at least know several did. I have pictures of at least 4 to 5 other 69 28's that have the shorter stripes. Pictures were supplied by John Mello and of course this post of the Hugger orange 69 z28. What I can say is that my 69 z28 has the original paint, built at the LOS plant, build date of 10D, shorter length rear stripes that match the factory assembly manual specifications and the shorter length rear spoiler (Longer length 1969 Camaro spoiler not available during build - factory used 1968 Camaro spoiler).
It's unfortunate that some owners of these early built z28's that came from LOS, had their car repainted to match the consensus that the shorter stripes are wrong and replaced their shorter length rear spoilers with the longer rear spoilers to match the consensus that the shorter length rear spoilers were also wrong.
I feel very strongly that if you have and early built 1969 z28 that came from LOS plant, with the original paint having the shorter rear stripes and the shorter rear spoiler, that this is an indication of Authenticity of a factory built 1969 z28. The only other camaro that came with rally stripes was the pace car, I dont know if LOS made pace cars. It is also unknown the value these unique z28's may garner, maybe higher value, maybe lower value. But, for sure, they are unique and verifiable as a factory built 1969 z28.
Like to hear from John z or Jerry McNeish.