Good question, I'm not sure which model they came from. Here are the 2011.10 ASR files and sizes I have if this helps:
01XS2BR4.SRX 1.6MB
01XS2BR5.ASR 45KB
01XS2BR6.ASR 1.02GB <--- much larger
01XS2BR7.ASR 113.4MB
I did see that 2011.20 files were available, but I didn't bother with that release because the ASR files are about 1/2 the size of the 2011.10 files I have. It seems there are at least two different sets of ASR files, the larger set seems to include the necessary data to understand Canadian cities and street names. I know this because when I first got my DNX9960 with 2010.10 map, the ASR files were also about half the size. With that release I had to search for addresses with the keyboard, but after I upgraded to 2011.10 (with the much larger ASR files) I magically was able to search Canadian addresses with voice commands. Since I'm living in Canada this is a pretty important to me.