Yes, this is possible. You shouldn't need to reinstall tools. Everything that Galaxy modifies is in (by default) three places on the filesystem (in addition to the database):
- GALAXY_ROOT/database/ - especially GALAXY_ROOT/files/ (datasets) and GALAXY_ROOT/dependencies/ (tool dependencies)
- Configs in GALAXY_ROOT/config/ - the ones modified by Galaxy itself are mostly the shed_*.xml files
Typically the easiest thing to do is to move the old GALAXY_ROOT out of the way and copy your configs to the new config/ directory, and move database/files and database/dependencies to the new database/ directory.
If you need to change any paths things can be quite a bit trickier.