Do some schools just look at last 60 credit hours for GPA?

[Scrubz]

My freshman and sophomore years I made mostly Cs and some Bs, and not really until the last part of my sophomore year did I kick it in and start getting just As and Bs. I've heard that some schools look primarily at last 60 credit hours and science classes as means for judging GPA. I mean, by the time I've graduated with my BSN I'll have more than a 3.0, but less than a 3.5. If my last 60 hours are called into question, it'll make my GPA look worlds better. I know not all schools just look at the last 60 credit hours, but I've heard some do, and I was just going to ask if there was any truth in that. Because if that's so then my last 60 hours will look good, and my science GPA right now is a 3.0, which I can hopefully raise. I'm mainly asking this because if I have to I guess I can retake some of the classes I took as a freshman to boost my GPA. I really don't want to, but if it'll greatly increase my chances later on of acceptance into CRNA school, then I'd do it. My biggest regret is my lack of effort in my early college years.

Thanks for any help.