Answer: The regular re-installation process will work for an earlier build. HOWEVER, the post-upgrade process will NOT copy the data from your current Foxhound database to the one that's being installed when the current installed build number is later than the one that's being installed. That means you lose your sample data and option settings, and it means you will have to activate Foxhound as if it were a brand new installation.

You can preserve some of your data if you plan ahead and take a backup of your current Foxhound database before installing a new version. Then, if you decide to re-install the old version, you can do a restore rather than run another installation process. You will lose all the sample data recorded while the new version was running, plus all the changes you made to option settings... but you will get your old data back and you won't have to activate Foxhound again.

See also...
How do I reinstall Foxhound?
How do I backup my Foxhound database?
How do I backup my Foxhound database on a regular basis?
How do I restore the Foxhound database from a backup?