I have this config:

# list of blocks not to convert when the above option is enabled [default: bank, meaning convert all, format e.g. minecraft:chest]
S:LOOTABLE_TE_BLACKLIST <
  minecraft:dropper
  minecraft:dispenser
  iceandfire:desert_myrmex_cocoon
  iceandfire:jungle_myrmex_cocoon
  randomthings:specialchest
>

But Pirate Ships from Quark mod still spawning with Lootr chests instead of Dispensers:

Same behavior with all other blocks in this list in different structures, from Mineshafts to Myrmex dens.

debug.log

These options were left in the port by accident and don't do anything on 1.12; sorry about that confusion. You should put the blocks in ADDITIONAL_CHESTS and enable CONVERT_ALL_LOOTABLES_EXCEPT_BELOW instead.

I will remove the options in the next release.