libstdc++ still has license conditions of SGI STL on top of GNU GPLv3+GCC Runtime Exception, right?

[P. -]

Hello, everybody! Libstdc++ (I took libstdc++-v3 with last changelog date
2019-12-30) contains comments like:
 * Copyright (c) 1994
 * Hewlett-Packard Company
 * Permission to use, copy <...> both that copyright notice and this
permission notice appear in supporting documentation <...>
 * Copyright (c) 1996
 * Silicon Graphics Computer Systems, Inc.
 * Permission to use, copy <...> both that copyright notice and this
permission notice appear in supporting documentation <...>
in header files <vector>, <memory> and etc.

While the current license of libstdc++ is the GNU GPLv3 + GCC Runtime
Exception, I still have to copy "Copyright (c) 1994 Hewlett-Packard
Company", "Copyright (c) 1996 Silicon Graphics Computer Systems, Inc." and
the license text (because <vector>, <memory> contain templated code that
will end up in my binary) in documentation, is that right?

Alternatively, I saw on the internet that the *entirety* of the library is
under GNU GPLv3 + GCC Runtime Exception now and those license notices are
meaningless today. However, in the FAQ (
https://gcc.gnu.org/onlinedocs/libstdc++/faq.html#faq.sgi_stl) it still
says that libstdc++ contains code from SGI STL. Which is correct: do I have
to follow the quoted (in part) licenses on top of GPLv3+Exception's
conditions or GPLv3+Exception has overriden this? Did the original
copyright holder contributed the code under GPLv3+Exception and the license
notices are just left in error (because a third-party can't relicense the
code they don't own under a different license, but can, with compatible
license, add additional conditions to combination of original code with
their modifications)?

Best regards and sorry for my English - I'm not a native speaker.