I think you missed a bit there, the rules say GK do NOT have access to annihilators
That aside, it could be oversight although the following sentences lead me to believe it is intentional, the 5d6 AAF is specifically listed for strike cruisers and not all GK vessels. The only thing that I can see the BB getting is the boarding rules as those are applied to GK as a whole.
The upgrades I was referencing were for the Replace launch bays section.
Also as written, GK strike cruisers are insanely fast on AAF since they roll PLUS 5d6 for AAF, not a flat 5d6. As written, it gives GK strike cruisers a total of 9d6 CM on AAF.