For step 1 you should also report the savetime and - most important - the volume.

Let me suggest the UNIX savetime - it makes things easier.

So your mminfo command should read something like this:

    mminfo -q "name=index: ,level=9,savetime>01/01/2015,savetime<02/01/2015 " -r "name,level,ssid,savetime,nsavetime,volume" -ot

For the rest I am wondering why you are interested in the index saveset at all if you do not want to get the list of backed up files? - If so, use

   nsrinfo -t

Besides that the index save set does not really make sense.

Remember that the file index is a 'nice to have' feature but it is not really necessary:

  - Worst case, you can recover the whole save set to a temp directory and get the files (subset) from here

  - If needed, the CFI information for a specific save set can be easily rebuilt by scanning the save set (scanner -i ...).

That should be sufficient for a decommisioned NW client.