i goofed - restoring a ISD file?

[Jerry Preeper]

I just made a big goofup with a perl script that imports raw data from text
files into tables in my database.  I turned off my backup program so I
don't overwrite the old files on the backup hard drive.  I just compared
the files from the database on the two hard drives and the only file that
is different is the .ISD file for this table.  Is it safe to just copy the
old .ISD file over the new one to restore everything from before my goofup
or must I do something different?
Jerry