[GMCPaul]

Yes step up plate besides connecting the cab to bed floor helps reinforce the middle section because it connects directly to the portion of the bed floor front crossmember. Towards the outer edge of the rear section of the floor the rocker box, rocker box end cap, rocker box reinforcement plates & Blazer rear floor supports under the Blazer floor help do this also as does the B-Pillar inside the front leading edge of the Blazer bed side. All those parts integrated together reinforce the Blazer cab floor. Front front to rear and side to side.
Paul Jr @ GMCPauls