1-First if i buy a used set of panniers of a 2016 to put on my 2017 are they the same? will they fit my oem racks ? if they are OEM then yes
2-If i want to use the keys from my bike on the other guy's panniers, do i need to go to a dealer or is it easy to reset the coding on the locks? you can do it yourself if you have spare tumblers, there are many YT videos, some dealers will do it for free, others not!