That section that is circled...
Think about this...
You have the Pre-Driver - then this empty spot, but if the radio is AM or FM - it doesn't need to be "fully populated" - in SSB, that section is used to drive - the Pre-Driver ahead of it, is a simple mixer buffer amp - you need the "missing section" to drive SSB (Linear amp) - else it's not needed so they simply jumper over it to the Driver and Final for AM/FM modes. (Class D and above)
It would explain the missing Trim-pots, you don't need them for Biasing in AM or FM (Constant carrier power) modes. You don't need the circled section if you don't need the stage to drive linearly for SSB.
Galaxy and Connex - and Ranger follow suit.
You see this - but that is a "955" board populated for something else, much like how Galaxy populated (even swapped) boards for the 29-73 for - AM/FM then convert for fully populated for the 77 - 99 series that have AM/FM/CW - SSB.