VIN number - cab swap

[crosby]

I just picked up a 77 K10 stepside, and hope to save the frame and build a decent driver for my plow truck. I looked on the dash where you usually see a vin and there is nothing there. Is the vin only on the door opening on the cab? I saw a plate there with a vin, but it has been painted over. I want to use the cab from my K20, but it's an 87, and I want to keep the truck pre-smog (1985 for NH) by running it as a 77, if possible. I know there are some sticky issues surrounding that . Anyhow, is there supposed to be a vin plate on the dash? Did somebody maybe cover it up with a new dash or dash cover? Also looking for a cheap carb just to make the stepper run before I tear it apart. It is complete except for the carb. Thanks very much guys!