No such thing as a '55-'57 Chevrolet 1 1/2 ton LCF. check the gvw, on the ID tag in the driver door jamb. If it's 16000lb.'s, it's definitely a 2 ton. Never heard of one having 18"in. wheels either. There were the 5000 series 2 ton medium duty LCF's, then the Heavy Duty 7000, & 9000 series LCF's. I've owned two of them. A '55 model 5400 series 2 ton, & a '56 model 5700 series 2 ton.See more here,
http://www.classiccoe.com/oldcoetrucks/5459.htm
