According to UK security vendor Sophos, the shipping version of Flash in Snow Leopard (10.0.23.1) isn't the most recent. In fact, it is a few months old and likely would have installed over a newer version had you kept up with Flash updates.
Sophos being a security vendor, reccomends Snow Leopard users to update to the latest version of Flash, lest they be vulnerable to the latest security attacks aimed at Flash users. To find out what version of Flash you are using, head to Adobe's Version tester here.
