No, it is the original backsight. Although I found a written reference to the backsight being swapped out for one with a ladder, the only pics I can find of a Beck version seem to have the same sight. I can only assume that the scaling was altered to match the improved trajectory of the M72 cartridge which was introduced at the same time as the Beck conversion, but have not yet found any pics to support this theory.
But before worrying about that: is the rifle you are looking at the Beck version?