Looks like the strings on this pole has required attention multiple times through the decades to where one can't be sure which strings are the original. If I had to guess, it is likely the three remaining dark brown disks. It's tempting to say the J-D disks are, but not so. This company was hanging J-D strings as late as 1968! (Image clipped from Google Maps - I intend to go up that way next summer - hope it remains intact until then)