Yes, that is correct I pulled that code straight out of the /modules/welcomeblock.php file. The thing to remember is that each template calls variables from an associated php file, sometimes trying to figure out which file can be a pain however. This is where turning on
Debug Mode can be handy because it will allow you to see each template associated with it's related php file.
The (newly implemented) plugin system was designed so we can just add specific code to designated areas according to where they fit. As to where before you had to manually edit the .php file and then re-upload it. It also gives you an option to turn it off and on which is another great tool when it comes to testing.
Mostly it's a matter of digging and experimenting at first, ensuring that you backup every single existence of every change so you can put things right back to the way they are in the event it doesn't work. You can also have a look through some of the tutorials in the Article forums for some how to's that will help you gain a better understanding of vB and how it works.