LICENSE and implicit LICENSE_FILE

Hello to all,

I can't find an answer for my doubt about if there is a implicit
LICENSE_FILE for LICENSE and this way we could use LICENSE without
LICENSE_FILE?

e.g.
---
LICENSE=BSD3CLAUSE
LICENSE_FILE= ${WRKSRC}/LICENSE
---
is the same as:
---
LICENSE=BSD3CLAUSE
---
assuming "LICENSE" file name is implicit?

I've searched at ports/Mk/* but I didn't find its proof and Porter's
Hanbook says:
---
Example 33. Simplest Usage, Predefined Licenses

When the README of some software says "This software is under the terms of
the GNU Lesser General Public License as published by the Free Software
Foundation; either version 2.1 of the License, or (at your option) any
later version." but does not provide the license file, use this:

LICENSE=	LGPL21+

When the software provides the license file, use this:

LICENSE=	LGPL21+
LICENSE_FILE=	${WRKSRC}/COPYING
---


So big question is:

Should we use LICENSE_FILE whenever LICENSE file(s) exists on ${WRKSRC}?

Thanks,
-- 
Nuno Teixeira
FreeBSD Committer (ports)