Well, as you said, the name
foo_VVV-RRR_AAA.deb for a deb file is just a convention for naming
.deb files, where
AAA are the version, revision and architecture of the package
Also, this convention is suggested (dictated) when building packages with debuild or git-buildpackage.
If you agree with this convention is ok, if not, you can rename your
.deb files as you wish, but only by following these rules (in this case maybe you must to run
dpkg --info <deb_file> to find a simple information that normaly you can get using the above convention for a deb file name).
Now, as you can read at Filename - Wikipedia:
There is no general encoding standard for filenames.
Because file names have to be exchanged between software environments (think network file transfer, file system storage, backup and file synchronization software, configuration management, data compression and archiving, etc.) it is very important not to lose file name information between applications. This led to wide adoption of Unicode as a standard for encoding file names, although legacy software might be non-Unicode-aware.
[...] Filename maximum length is not standard and might depend on the code unit size. Although it is a serious issue, in most cases this is a limited one.
So, if there is no standard for file names in general, I am almost sure that there is not a special standard for
.deb file names. Or, if you are still confused, take the convention as a standard, and follow these rules.