Unless it can be shown otherwise, as it currently stands I agree, you need to use JTAG to get the memory dump for the DS/MSO1000Z series as they don't have a RAM read SCPI function. For the avoidance of doubt, for the DS1000Z series, you don't need the dump anyway. But you do for the MSO1000Z series.
Sounds like there's been a bit of hearsay at play, and internet hearsay at that!