I am flying Y to DUS next week and, as usual, have gone to MMB to get a decent seat. The return sector seat map shows an 'A321' with 33 rows (and no mid cabin bulkhead, although two exit rows) . I imediately thought it should be B757, but on checking those seat maps, they go to 34. I am asuming it is B757 and therefore placing myself on a bulkhead row. Any thoughts on what is going on?