When ram is manufactured, it's a bunch of blanks. Not even a heatshield, nothing but a pcb with ic's. A vendor will contract the manufacturer and say it wants X amount of 2400MHz. So the manufacturer throws a bunch of ram through the binning process, set for 2400MHz, slaps labels and heatsinks and paint on it, throws a rambios in it with the jedec tables and you end up with a bunch of 2400MHz ram. In a nutshell.
What they don't do is test that ram to see if it's 3200MHz capable. Why bother, they only need 2400MHz. Your particular ram could very well be 4000MHz capable, nobody knows, nobody tested for such.
On the flip side, it's entirely possible they are failures. Those sticks might have been tested for 3200MHz, failed and got stuck on the failed bin for testing at a lower frequency. So may end up as 2400MHz maximum or 2666MHz. Nobody knows. You will not find out until you try, nobody can give you an answer as to yes or no they will work.
Default settings will put All the ram at 2400MHz, doesn't matter if some of the sticks are higher. If you OC the 2400 to 3200, 2 of the sticks will handle that, it's their rated speeds, but whether or not the 2400 will still be stable is impossible to determine on our end. Only the ram itself can give you that. It'll either work or not.