No, that's much more complicated than necessary. They can upgrade by clicking the "Upgrade Now" button on the "Preferences" panel of Tunnelblick's "VPN Details" window. They could download a new version of Tunnelblick and install it by double-clicking, but that's a lot more work. Their configurations and settings are left intact when re-installing on top of an old version..
Note that upgrading from such an old version can cause problems. If that happens, see
Tunnelblick 4.