I tried asking, years ago, with the rationale of I'm not wasting people's time, since they could get more money if they knew about bootloader unlocking.

Then I decided everyone who knows about bootloader unlocking would've already checked and mentioned if it was unlockable (but not if it wasn't, since why confuse normal buyers with a fringe thing), and I've never gotten a positive response trying to tell any seller about it, so I think I'm just wasting everyone's time.

Your mileage may vary.