Composite glider life hours are an arbitrary number, put in because the certification process requires it to have one. There has never been (I am willing to be corrected here) an instance of fatigue failure of a composite construction glider, and examples are flying that were built over 50 years ago with many hours airborne. The manufacturers can (and do) produce a life extension process when one reaches the certification life.
Release hooks have a number of launches before exchange and replacement or refurbishment; this is a manufacturers (TOST GmbH) figure. Since many have separate aerotow and winch releases, it is theoretically possible to have a glider which has only used one form of launch, but has to have an unused release replaced. (The one never used for launching would of course be exercised every time the other was used for launching).
Other items, such as harnesses, have a calendar life (normally 10 years before replacement or refurbishment).
It would probably be logical in a sane environment to do a life extension as part of the Viking return to service, as the inspection is all being done in any case, but this is unlikely to be in the commercial interest of anyone involved.