When I acquired this No. 2 many years ago, an offset printing blanket (the press was being used for perforating/cutting prior to my getting it) was clamped between or under these flat bars. I replaced the blanket way back when and took these bars off and used the square cinching bars to tighten the blanket.
While cleaning the press up after it had been sitting for many years, I found these bars and noticed that there are 3 registration pins on the outer bar. You can see them right at the edge of the bar next to the socket head cap screws that hold the two bars to the cylinder. The two bars are held together with 3 countersunk screws from the back of the bar that is against the cylinder.
Does anyone know what this bar is for, how it is used and what the registration pins are used for?
No. 2 Cylinder flat bars
My guess is that it is for clamping the lead edges of all packing. That there are two take-up reels suggests upper and lower packing. I doubt the two reels were meant for head and tail, even if set in opposing directions.