Hello,
I have some customers who did that, and in fact it is quite easy.
The way is to do basically a "select distinct doc_name from segment_tables" in the Library Server of CMOD (could be DB2, Oracle or SQL Server doesn't matter).
Do the same with TSM (you have to do a select on the archives table if I'm not wrong).
Then with the 2 outputs, you need to do something like a "diff", and then you're ok :-)
Well, then you will also need to check the OnDemand resources, that are also stored in TSM...
By doing that you will see that in TSM you'll have more objects than what you have in the library server :-) but you don't need to care about them!! At least not for what you intent to do!
Good luck