digi ME part numbers

I have several DigiME modules, some old and some later, which I am trying to relate part number on the device with the part number/ description given on the web site.
The original ones are 50000866-01 and later ones are 50000878-08
I think the first are 2Mbyte memory and second are 4Mbyte memory. But how do I work out what they are similar to with the web site part numbers.

Hmmm, for reference, my 2MB JTAG is -04, and my 4MB JTAG is -09. I have some old 2MB modules that are -01s too.