The fender emblem will say it is a C series, perhaps a C60. The driver's door post should have a tag with the VIN which can be decoded. There will be a plate on the driver's kick panel or door post with the gvw rating. The 350 was not installed in trucks till 1969, at the factory, but anything is possible. You will have to check the numbers on the engine to be certain. The curb weight will depend largely on what the dump body weighs, there may or may not be a tag somewhere. Nice truck.