Yeah, I used to work at Tektronix, this looks like an A unit.
Also, the 50GS/s is actually more like 25GS/s as it has a Nyquist frequency of 12.5 GHz.
This is because they take 2 samples at the same time, instead of 180 degrees out of phase.
I wish they had made that clearer to customers, it felt misleading to some.