Yup. Actually the one on the earlier picture (my own desk) is on the same arm - you just don't see it.
I've also used the Ergotron arms, but this one - made by Innovative - is better. You can buy them on ebay (new) for a lot less; I have the big one for a 30" monitor and it was $100 rather than $450:
http://www.lcdarms.com/He's set up differently, with the computer keyboard in front of the MIDI keyboard, but that's just the way he likes to work.
Oh, and the reason for using the LCD arms isn't as much that you can move them as that it floats the computer monitor in exactly the right position. You can move them out of the way, but I never do.
A composer friend of mine actually had his glasses focused to the distance he sits from his monitors.

He still has CRT monitors on a different desk he bought years ago. But it works for him, so..