Both _Attack of the Clones_ and _Revenge of the Sith_ were projected digitally as well as on film. And yes, if you looked closely at some points you could see the pixels on the projection. (Although _Attack of the Clones_ was also one of the first movies shown in IMAX via process of taking a 35mm film print to IMAX film[0]. So with _Attack_, instead, they upconverted a 2K master that was derived from 1080p source to IMAX film stock (as far as I know). Yes, it had a lot of weird smoothing artifacts when seen projected on an IMAX screen.)

[0] http://en.wikipedia.org/wiki/List_of_IMAX_DMR_films