Folks, I'm a bit mystified with the track frame roller bolt holes on this unit - I was attempting to clean up the 5/8-11 threads that I was expecting to find in the track frames, used for securing the main rollers, but all of the holes I checked appeared smooth with no evidence that I could find of there ever having been threads in there. I did see a couple of holes gas-cut in the side of the frames so I was able to get a good look at a couple of the holes from the top side. The parts diagram shows only the 0S1572 bolts and 3B4510 lock washers and no nuts or nut strip.
Could someone let me know if those holes are supposed to be threaded originally. What I could do is blow holes adjacent to all the other holes and put nuts inside, and then plate over the holes afterwards as a solution
 

Many thanks Phil, I just looked that up using your reference and sure enough, there they are. I'll see if Florin has two, just need them for one track frame.