KenV, this isn't my area of expertise (I'm an engine guy). But my understanding is for Boeing built 747 Freighters and Boeing Converted Freighters (BCF, which is what the Bagram freighter was), they don't use seat tracks. The floor structure is someone unique to the freighter (and yes it is strengthened relative to the passenger main deck floor). The 747F main deck has a fairly elaborate cargo handling system which incorporates stops and hold-downs for the standard air-cargo pallets. Unfortunately those are not suitable for hauling large military vehicles, so alternate means are required.
Freighter conversions done by others often repurpose the seat tracks for cargo restraint, but not those done by Boeing.
However the rest of what you posted appears spot on.