postgres restore & needed history files

We are using a DIY Postgres backup:
---
psql -c "select pg_start_backup ('Full');"
save -s "${NSR_SERVER}" -g "${NSR_POOL}" "${PGDATA}"
psql -c "select pg_stop_backup();"
---
The pg_wal directory is not saved with it because it is a linked directory.

After some time, we had to perform a point-in-time recovery of 1 of the 5 databases to a point in time 7 days in the past.
We tried to perform a point-in-time restore on another host, which did not work until we copied the contents of the current pg_wal directory.
The current pg_wal directory included 8 history files: 00000002.history to 00000009.history.
The point-in-time restore worked smoodly after it had all these history files.

Afaik, all necessary history files should also be restored by the restore_command.
I had a look at our archived wal backups and found that 00000002.history to 00000008.history files already had been deleted due to our NSR backup retention of 30 days.

Question: Is it necessary to retain all history files?