Question for Caravans International Munro Ltd

Hello, i have a question, i wanted to buy a Ford Trader 1988, CI Munro coach. we wand to travel with this camper in NZ, we have two kids, this modell doesn´t have seatbelts on the back seat, is it possibil to put then in? Is it allowed to carry kid in camper on back seat. (See the Camper on Treadme ********) thanks for a short answere. Benny