Upgrading old RH server

[Ashley M. Kirchner]

    We have an old RH7.3 server that holds all of our user accounts.  
I'm in the process of upgrading everything to FC10 and looking at 
/etc/shadow I'm noticing some differences in the way the passwords are 
encrypted/stored.

    RH7.3's string looks like this:
        $1$9cgDnjV/$SLqsoxfwr6tr3o7QkdQ3j1

    Whereas FC10 looks like:
        
$6$KS2xrBPJ$jXiz1pE9Lpcb8sSSU0ZHifeN9wBwc.k7GdWO4KIJ3F2JqEw/1mD7bPO6b4jvRXiyXrQn0noWPfs.0h6/tjKbe0

    I tried simply copying the old shadow file to a new FC10 server and 
it seems to work just fine, however I wonder if I'm not breaking 
something else by doing that.  So, what's the proper way to do this?  I 
really don't want to have to reset everyone's password (at least not 
till they reach their forced expiration.)

    Thanks.

    -- A