Craig, I believe the '51 and later style spare mounts can be installed on an earlier truck. Although access to those is not easy either. I recall ripping the spare tire out from underneath a '72 K10 I had when I was gathering firewood. A stump I ran over did the deed. A lot of people here in Alaska back in the 70s installed front mount spares, but they blocked the radiator airflow and subjected the truck to increased damage in the event of what would normally be a bumper tap accident. I never used one of those.
