Don't know what kind of money your looking at, but a good cab & doors, with a hood & grill pieces are worth spending some money on, especially if it has a title. I've been looking for a decent cab, hood, and grill pieces for a while. They are not easy to find, and most I find that are decent are pretty high priced, or across the country, which adds at least $1,000 to the price. I bought a rusty cab in April, it has no floors, rockers or door bottoms, the doors are gutted and there is no glass, windshield frame or hinges. This is just the rusty body, there is no frame! I did get a hood, grill & box sides, but none of the rest of the box. There are no fenders, and there is no paperwork. I was excited to buy it for less then $1,000! I have a pair of 1 ton front fenders that are in decent condition (I have no rear fenders), if I put fenders on it, I will use the 1 ton fenders.
Modifying the fenders isn't that big of a deal unless your planning on laying it on the ground. The difference between the 3/4 ton and the 1/2 ton fenders are mostly in the back lower section and the wheel opening.

Given 1/2 a chance, I'd buy a 1 or 1 1/2 ton cab & nose,(frame wouldn't matter) if it was priced right, in decent condition (bigger trucks tend to have better condition bodies), and had a title. I've only seen rough ones in the $1500 (too much for me) range that were 1,000 miles away. I did miss out on a nice truck here on Moparts last year, when I didn't have any money. Gene