copying the blk .dat files from a backup to a new installation produces an error:
EXCEPTION: St13runtime_error
CDB() : can't open database file blkindex.dat, error 22
bitcoin in Runaway exception
This may not actually be an error, because of this commit: #1119
If this is not an error, it would be ideal to have a solution posted somewhere for users who want to force a "clean" shutdown of the .dat files for backup/restore options.