I think the amount of Iridium in typical (not the meteorite impact ones)mineralized (ore-bearing) Earth rocks is measured in a couple ppb (part per billion), down to parts per trillion; the two iron meteorite info sheets on the previously posted Metbase link were a couple ppm (parts per million) - it seems like even after taking into account the concentrating effects of smelting and the diluting effects of mixing meteoric metal and earth metal, there's room for a noticeable difference.
But it's all speculation until we get some data to crunch.
