Of course not, it's called binning. And forget consumer parts.Do you believe ram clocked at 2133 is fundamentally different from ram clocked at 1866? The lack of a an available consumer part is quite likely the lack of demand for such a part.
The only 8Gb Micron part is MT41K512M16TNA, it's split into 2 bins: 125 and 107 (it's the cycle time, 1.07ns and 1.25ns, so 1600 and 1866).
However the 4Gb part is MT41J256M16HA is split into 4 bins: 125, 107, 93G and 93.
So the 4 bins are 1600, 1866, 2000 and 2133. It's the same silicon.
So the bins available for the 8Gb parts don't go above 1866. You claim they bin them to 2133 in large volume, and there's zero proof of that. It's not impossible, but you're the one claiming it exists, and an opinion is hardly a proof of it's existence.