NEED HELP!! Messed up Rear Caliper bracket。
 

I messed up the rear caliper brackets. One with number 2XY and the other is 2XQ. (I painted the other side so can not see anything). There are two nuts on the bracket. As the pic shows, one black and one aluminum color. Can anyone tell me which color is the upper one? And I just wanna confirm that for the front bracket, the black nuts was the upper one.
Thanks.

so the fronts ones are with number SR and SL. And rear ones with number 1 and 4 or 2xy and 2xq