OK, so I just re-ran the SDRAM dump - exactly the same way as before. Same output file size, same gdbproxy messages, etc.
And, go figure, there's the key! Now, the thing I did which was different than before was that I made sure the scope was in RUN mode. Last dump I did, I had the scope in STOP mode, so not sure if that had an impact, but it sure seems to have worked!
Now, I'm going to try to use the DS2072A model name to generate the licenses...