Yes, the acceptance rates for the COE of some of the publics will be much lower thatn their other colleges. Even for instate students, it is not easy to get into UIUC for Engineering. Check out the college selectivity within UIUC.
http://admissions.illinois.edu/apply/requirements_freshman.html
As you can see, for the COE, the caliber of students is much better as compared to the other colleges. The same holds true for all the publics known for their Engg. school - UTAustin, UMich, UCB, GTech, etc.
UMich (2013) - http://www.engin.umich.edu/college/about/facts
UTAustin (2014) - http://bealonghorn.utexas.edu/whyut/profile/scores
GTech (Freshman 2014) - http://admission.gatech.edu/life-tech/class-profile
The admission criteria/stats for OOS students to these top publics for their COE are equal or better than some privates with lower acceptance rates. I have provided the stats for Tufts and Emory as a comparision.
Tufts (Freshman 2014) - http://admissions.tufts.edu/apply/accepted-student-profile/
Emory (Freshman 2014) - http://apply.emory.edu/discover/fastfacts.php