Nope...

It's an update, not an install. It simply updates certain files, but not all of them...

If you're worried about the update, then you can make a copy of your 3dgs folder. You can have seperate installs, since 3DGS doesn't depend on the registry... The only problem you might have with this is shortcuts (to WED, MED, SED), as you'll have to keep track of which ones point to which version...