I have some wild caught G. brachybranchus and they look quite different from yours. Yours have a lot of orange/rust coloration in the chest and on the flanks. Mine show none. Also the striping is more continuous on mine. Yours are definitely not 'winemilleri'. Here's a couple of pics .
I had a group of brachys that showed a bit of variation. A couple of the females had more orange/red in the chest and showed the scattered/broken blue iridescent lines, but the males didn't really show the red and the blue iridescent lines were continuous. They all show the black throat and the preopercular mark.
Alon, do yours have a preopercular mark? It's hard to tell in the pictures. It could just be not showing. G. brachybranchus should have this.