I took a look at the catalog you referenced. All of the watches you show above are manual wind, which would have a slimmer profile than a bumper automatic.
There is a section in that catalog with just automatic watches, but none of the cases match your original post. All this means is your particular case was not made for the 1955 model year. With US made cases, it's almost impossible to tell what year they were made. The serial number on the movement would indicate a 1954 (or so) made movement, but it may not have been cased until several years later.
I'm not sure what you are trying to prove here. I see no reason to doubt the originality of the watch.
It is a 1950's US market Omega Automatic. Everything looks good to me, even the buckle.
gatorcpa