vdocad

On a previous post I detailed the issues I am having with multiple engine codes. I replaced all 4 O2 sensors and two codes are still there, P0141 and P0161(both downstream) and could the the reason I am getting P0300.
When I purchased the sensors, they came with no documentation as to which goes where. Two were identical and had a white plug and a bunch of holes on the tip, and two were identical and had a black plug and only a few holes.
Parts retailers advertise O2 sensors for the Chevy Express as being the same for bank 1 up or downstream, or bank 2 up or downstream. I also read that the most important ones are the upstream. So are the upstream identical to each other and the downstream identical to each other? Are the upstream ones the ones with more holes and the downstream ones the ones with less holes?
As it is right now, following the connector colors, I have both sensors with a lot of holes on bank 1(up and down) and both sensors with less holes on bank 2(up and down). This could be the reason I am getting codes
Any thoughts?