Front and back eyelets are a comonplace, I have them on my mountainbike too. As BWG says low riders are the norm, and they are put on the lower rear ones. None of these eyelets are designed for racks, and the parts regularly fail when used on uber long tours, due to the fender weight 5mm threading.
There are two eyelets because some fenders use 2 or more front wires. There is only one frame pass by to attach the fender to up front, so extra wires can be used. These days, that is considered antiquated as most front fenders are short in the forward extension and this doesn't affect coverage. While good touring bikes often have the double eyelet, As BWG notes, most touring rigs don't actually use both of them.
What should be, are no eyelets, two massive front braze ons for minimum 6mm bolts, and the fenders should attach to the rack and be designed for the 6 mm bolts. Integration of the fenders and racks is better still