The answer: No. I know this to be true from personal experience.
Years ago someone gave me a 15 year-old A. obesum grown from a cutting. Last year I nearly killed it by over-watering. When I un-potted it I found huge succulent roots that had rotted; at that time I mistakenly thought it was the caudex. Here he is now going on 32 years old. As you can see he does not have a fat caudex, but he does have a nice thick trunk.
"If you're like me and you're growing this succulent plant because of the 'fat trunk' (caudex) you should know that a plant produced from a cutting will not grow the caudex that attracted you to these plants. If you want an Adenium with a fat trunk you have to grow one from seed, cuttings will still develop into nice plants but the trunk of the plant will not be all that interesting. You should also be aware that many of the Adeniums you'll find that don't have a large caudex are grafts. A piece of a Desert Rose that produces great flowers is grafted onto the root stock of an Adenium that is common or is known to have strong roots. A cutting from the grafted piece will kind of defeat the purpose since you'll be growing the plant with the weaker root stock."
The above is from:
http://mrbrownthumb.blogspot.c...
