Hello Michael. Strange you should post your seat belt question right after mine. Anyway, if you "google" automobile seatbelt" you'll get a nice list to go from. Some I noticed were a lot cheaper than Moss etc. Some even offer both types of fastener (hook type, or bolt on). One company, "Snake Oyl" will restore your old belts or sell new ones. One company, the name escapes me, is now having a sale, you can buy the lap belt type in various colors with the aircraft style of latch for only $19 plus $5 postage.
Good luck with your search, let us know what you bought.