Texas A&M offers guaranteed admission to out of state as well :Academic Admits (top 25% & 1300 SAT or 30ACT with minimums). http://admissions.tamu.edu/freshman/admitted
To answer your question, is it harder to get in - can be answered with both a yes and a no. Yes, because OOS are not eligible for the top 10% automatic admit. No, because they are eligible for academic admit program. It has been said that residency does not count against you for review admits, however the competition for those few remaining slots is pretty fierce (12-13% admission rate) and flooded with TX admits.
Why the stats are deceptive : top 10%ers only have to take the exams, score isn’t relevant so many don’t even take the exam more than once, also conditional admit scores and admissions are included in the national stats released. Those students attend a community college part time & A&M part time then apply for full admission again later. This combination really skews the numbers and people are stunned when they don’t get full admission. Here’s a link explaining the breakdowns of Class of 2018 http://talk.collegeconfidential.com/texas-m-university/1676831-class-of-2018-offers-of-admission-breakdown.html#latest