Hey i am in the same exact situation as you. I have heard that GPA trends do come into affect, but only after GPA/LSAT scores are considered. They are to distinguish students of similar scores. So, if i am not mistaken, you will be chosen above a student with the same lsat score and a 3.4 gpa that has been steady throughout college. But, i dont think your trend will help you compete much with someone who has lets say a 3.5GPA. However, i am not 100% on this, if some one more experienced can chime in that would be awesome.
I am also a junior with a 3.19UGPA and an accounting major. I had a 2.0 gpa freshman year and since then have had a 3.9 gpa every semester and i took a winter and summer semester hah. Hopefully i will get another 3.9 this semester and have a 3.30 for my app. My advice is to focus on the lsat of course.