As long as there is no "R" in the designation, it is non-resistor.

My 1995 NGK catalog heat range chart lists a BP7EFS as a non-resistor plug - same geometry as TR5; "7" is colder than "5". The BP5EFS is not listed, so it must have been added in the last ten years, but all indications are that it should be equivalent to the H9DC.

Duke