From the accident report:
The Commander programmed the “APBSS (Blacksod South) Route” (See Figure No.4 above) into the FMS during the cruise and the Co-pilot confirmed that the route matched the Operator's Route Guide.
So they obviously didn't just blithely pull up the waypoints left in the FMS database from a previous task, they deliberately selected a saved route and checked it against the route guide.
Fixed wing FMS user here somewhat confused . We don't have the ability to look back into the memory (volatile or not) and use a route Bloggs built umpteen days ago, we can however select company approved routes (dep/arr page). I had begin to assume the accident crew had used a company generated route extracted from the database- presumably that was not the case?