this is actually the new PCB revision using Altery Cyclone IV already, which from FPGA speed7stability, clock jitter and waveformdistortion didn't really matter because Cyclone III and Cyclone IV
are not different in this category, but the board is a universal board for CAL and CML model - so with additional SRAM chip and (probably) different firmware you can "update it" to CML model.
About the cloning thigns - actually most chinese DSOs are using almost the same input stage (from 40 to 300MHz), there is not reason why they should
not do this, that's not cloning at all. Sure Atten CAL/CML board looks very similar to Rigol E board (except the LCD controller whish need to be different due LCD size)
but hey, that's only piece of silicon, the programming matters (FPGA, CPLD, DSP), there are billions of way to win or screw up the DSO design.