Well, if the credit says MK: lead guitar & rhythm guitar, it doesn't mean there was nothing left for DK. In many songs there are more guitar parts than guitar players, so you have to record an additional track.
... It's another subject, but I've never understood why he needs other guitarists in studio, because, they always play just few uninteresting parts, Mark plays all parts you can hear at the first listen, so why don't he record all his albums just like he did for MM and KTGC ?
Not really. When you look at live songs (I'm sorry DutchEssy for using this example), the reckognizable melody of done with bonaparte is played by RB. MK plays rhythm on the national which you can hardly pick out. The melody, especially the '96 versions you hear it well, is played by Richard on his Bouzouki.
And if you want to hear the impact of rhythm guitar, listen to BIA recorded on the 16th of April 2005 (Amsterdam). You'll see what happens when a capo is in the wrong position.
