Korean patched device has XKK as their start, and some more infos at backplate:
1. Model Name is MOD.HAC-001(-01), which means it uses different board than the original one but no difference in firmware.
2. Device's backplate, row 2nd, right after 2019 has HAD-S, instead of HAC-S.
This difference is because of the law of Korea South, saying there should be a difference when there's changes.
Please check this out before, if your device has same thing of 1 or 2. If the device has this differences, it definitely has patched.