It does help the joke, yeah. My disagreement is only on whether it counts as a joke in itself - but it is a nice (and easily miss-able*) detail.
* First time I read the strip, I did miss it, until his comment about her being like the movie, at which point, I read back, so, to be fair, I shouldn't say so much that I didn't miss it, only that I'd caught it before finishing the strip the first time.