Which SPDX Identifier for files without explicit GPL version

[Michael Straube]

Hi,

which GPL version should be used in SPDX Identifiers for files that
are GPL licensed but do not mention any version? It is not clear to
me after reading license-rules.rst.

For example:

/******************************************************************************
 * Copyright(c) 2008 - 2010 Realtek Corporation. All rights reserved.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * The full GNU General Public License is included in this distribution in the
 * file called LICENSE.
 *
 * Contact Information:
 * wlanfae <wlanfae@xxxxxxxxxxx>
 *****************************************************************************/

or:

/* IEEE 802.11 SoftMAC layer
 * Copyright (c) 2005 Andrea Merello <andrea.merello@xxxxxxxxx>
 *
 * Mostly extracted from the rtl8180-sa2400 driver for the
 * in-kernel generic ieee802.11 stack.
 *
 * Some pieces of code might be stolen from ipw2100 driver
 * copyright of who own it's copyright ;-)
 *
 * PS wx handler mostly stolen from hostap, copyright who
 * own it's copyright ;-)
 *
 * released under the GPL
 */


Should it be GPL-2.0 ?

Regards,
Michael