I don't think versions like:
$My::Module::VERSION = '1.23';
are the deprecated v-strings, despite being strings with version numbers in them. If you put a 'v' at the front, then it might be a v-string and I am more certain that if it was unquoted with a v in front that it would be a bare v-string. So, if I understand correctly, many people consider the following to be bad:
$My::Module::VERSION = v1.23;
On the other hand, see Re: Seeking thoughts on version numbers in modules - maybe v-strings (the magic variety as of 5.8.1) are OK after all. Still, my conclusion is that with so much contention, it is probably safer to use some other form (like what you are using, which is consistent with most of the core modules), at least until the dust settles on v-strings, one way or the other.