It would be good to ignore FR: Periphery 2765 altogether. It may just be the worst of the whole FM/FR series in terms of both ignoring previous continuity and for the inexplicable glossing over of the Rim Worlds military. The FMs are some of my favorite BT sourcebooks aside from the original House Book series, and the low quality of that entry was very sore for me in general. One of the few times I felt like buying a BT supplement had been a waste of money, and it sort of cooled off my interest in the whole franchise for a few years.
And no seriously, we know less about the Rim Worlds Military than the SLDF, even through the latter is about thirty times larger. For that matter, we know more about the Republic of the Sphere's military, and that existed for a mere half century in universe, and was cannon fodder for the most part. What the heck?
For a 3025 view of BTSD, we should use some of the material that was generated from the Empires Aflame fanbooks, since those did a good job of depicting Successor State militaries that kept or grew upon their strength from the start of the Successor Wars.