Do I have that right?

Hard to say, why are you looking inside? Are you trying to fix a bug? Tk::Optionmenu's addOption doesn't look well tested, so first thing to do should be to write tests.

If lots of people agree, I'd be happy to email the author but... I can't find the author for this module.

http://cpansearch.perl.org/src/SREZIC/Tk-804.028_501/Tk/Optionmenu.pm

# Copyright (c) 1995-2003 Nick Ing-Simmons. All rights reserved.
# This program is free software; you can redistribute it and/or
# modify it under the same terms as Perl itself.
[download]

Nick Ing-Simmons used to release Tk, but he is no longer with us. You can report bugs here