Here is what CBSA has to say. There is nothing about 6 months ownership of vehicles.
"(a) The vehicle must have been owned and possessed by the settler, in accordance with the conditions described above, prior to his or her arrival in Canada;
(b) In addition to having owned and taken possession of the vehicle abroad, the settler must have been legally entitled to operate it in the free environment abroad (e.g., have a valid driver's licence) and have actually driven it on the open roads abroad for some distance, prior to the date on which the settler arrives in Canada. (note that a test drive using dealer licence plates or a drive only on the manufacturer's or dealer's premises does not qualify);
(c) The vehicle must have been licensed and insured (temporarily or otherwise), in the name of the settler, for use in the free environment abroad during the period it was used;
(d) Documentary evidence is produced at the time of accounting to substantiate that the above requirements have been met;
(e) All of the remaining requirements of Tariff Item No. 9807.00.00 are complied with; and
(f) The vehicle is eligible for importation into Canada in accordance with Transport Canada's laws and requirements."