Instead of just skip if it is in the blacklist,check it later and if it is in blacklist,destory the gui.

at line 459:
script.on_event(defines.events.on_gui_opened, function(event)
  local player = game.players[event.player_index]
  if
    event.gui_type == defines.gui_type.entity
    and event.entity.type == "inserter"
    and settings.get_player_settings(player)["bobmods-inserters-gui-position"].value ~= "off"
  then

    if
        event.entity.prototype.allow_custom_vectors
        and not(global.bobmods.inserters.blacklist[event.entity.name])
    then
        global.bobmods.inserters[event.player_index].position = "left";
        bobmods.inserters.open_gui(event.entity, player);
    else
        bobmods.inserters.delete_gui(event.player_index);
    end
    --[[
  else
    if not (event.gui_type == defines.gui_type.custom and event.element.name == "bob_inserter_gui") then
      bobmods.inserters.delete_gui(event.player_index)
    end
    ]]
  end
end)