From the reading I've done the early build 03's are the ones to stay away from.
Having said that if you did your research, brought a monitor on the test drive and everything checked out $14k is a good price, just know what you're getting into.
When we were shopping for ours we liked the look of the 05 better and the 03's had the most negative press so when I started looking I looked for an 05. Would I steer clear of an 03 now that I've learned a little? Straight up NO... I've learned enough to realize that there are products out there to make any 6.0 bulletproof. If you can turn a wrench (or want to learn how) for $14 you could put $10k into it and come out with a great bulletproof truck. At $21 for an 05, when you put $10k into it you have a more expensive, great bulletproof truck!
Regarding the one you're looking at... head studs are not the issue with the 6.0. The issue is maintenance, oil changes and more specifically coolant. If the coolant is neglected it clogs the oil cooler. The clogged oil cooler overheats the EGR cooler. The overheated EGR cooler ruptures and you get coolant into the cylinders. The coolant in the cylinders increases the pressure in the heads. The increased pressure stretches the head bolts. The stretched bolts blow the head gaskets. Or something close to that!