I too have an Epson printer (Stylus Photo R340) that was working properly with 10.6.2 and yet the Apple SW Update indicated I needed the 2.1 update.
After making and verifying a backup, I installed the recommended updater. In my case the updater apparently installed OK, but I do not see any consequence from the updater; only now there are no indications that I need an update. Yet there are features such as printing CD labels that I do not use, so maybe things are changed in that regard. I dunno.
So I say, gopher it, but ONLY if you have a backup. As always there are reports from those who claim their printer is broken after the install, so indeed a bit of caution is required.
If you do install the updater, please post back of your success (or not).