Hard to say... I can tell you currently that pretty much any Ryzen will run fine at stock with the paired cooler. Not to their best, but absolutely as advertised and IME at reasonable noise levels. Even under heavier-than-gaming loads. Most people (I think) will say the same. Bear in mind that while yes, the lower end models get your basic urinal-cake style coolers, they really don't require much more. These are pretty low-TDP chips, especially under normal usage scenarios. For instance, my 2600 OC'd to 4ghz isn't pushing much more than 60W max on current titles... and it's averaging more in the 40's. With a Dark Rock 4 on top, a midrange, mid-tower cooler, it's a rare day when CPU temps pass 55C. That cooler is expensive. But I also have an inexpensive Sythe Mugen Max that cools just as well, if not better at times. And this is in an NZXT S340 Elite, a compact ATX with somewhat modest airflow. I'm betting Zen 2 will be even more efficient due to node shrink, so it's hard to imagine the stock coolers not keeping up for anyone not concerned with overclocking or very heavy, non-gaming usage. Though even if you're planning to really put the chip to work, at most you'll have more noise. Temperatures will likely be manageable.
Speculation based on what we've seen with Ryzen so far. Zen 2 is quite the overhaul, so anything goes. Grain of salt.
Okay, so, here's my real take on the stock coolers. They are great when you're starting off on a build and maybe your full budget hasn't manifested yet. But the value of having those coolers available from the jump is not THAT high. To put it into perspective, for around $40, there are a multitude of AM4 coolers out there which will offer you near-silent operation under all but the heaviest loads and a max overclock (or boost for the x models.) Not a lot of money for what you gain in return. Even a Hyper 212 would serve you better in most cases. Ryzen is pretty easy to cool. Good air coolers can be had cheap. It's just such a trivial upgrade, you know? And a good aftermarket cooler, much like a good PSU (wink) will persist across builds and part swaps.
I'm recalling a time when people used to be angry about stock coolers being included with certain CPU's simply because they were basically destined to be swapped out in order to tap into the full power of the chip, thus only adding to the cost unnecessarily.
That's me though. If something significantly better is just a little more money in the big pot, I think I'd be a fool not to grab it and risk being left wanting later. You want the X model. The stock cooler is probably okay, but the main selling point of the X models is their ability to boost higher automatically with better cooling. If you're not going to capitalize on it, you would lose very little going vanilla instead. A major upgrade is only as good as the platform it stands on. For a little more money it can shine much more.
Basically, if you're asking if the stock cooler will be suitable, the answer is probably going to be "yes." But whether or not you're truly getting your money's worth sticking only with that is debatable.