Ive always wondered what years they put the auxillery gas tank cap inside the truck bed? Mine is actually the only one ive ever seen before. When I first got my truck and I saw it, it blew my mind lol. My truck is a 73 but my grandpa put a bed on it from a different truck probly about 15 years ago. Does anyone know any information on this? I thought I had a pic of it but I cant find it and I just put my bedliner back in for winter so I cant take one now.