HT1000 come in several varieties, some of which can do narrowbanding. The second to last digit in the model number determines the radio Version. If the 11th digit in the model number is a C or a D, then they are capable of being programmed with 12.5 khz channel spacing. Ie, the radio I have is H05KDD9AA4BN, and is not capable of narrowbanding, since the 11th digit is B.
MT1000, HT600, and other "Genesis" series radios also come in several varieties, and none do 12.5 khz spacing. They do make wideband and narrowband versions of this radio, but that simply means 50 khz vs 25 khz spacing. Remember, the definition of narrowband has changed in the past 25 years since these radios came out