If an index is used: http://blog.sqlauthority.com/2008/10/03/sql-server-2008-find-if-index-is-being-used-in-database/

You can tell, but restarts will clear your stats.

There's also a good piece from Kimberly Tripp on duplicate indexes that's worth reading.

FWIW, I'd make sure all of these are checked into TFS and if you remove them, then put the removal back into TFS for the same index as the HEAD script.