You can not shoot the difference between having them all trimmed the same length, and not. I don't care if its an AR or a LR bolt gun. The concern with trimming is not letting brass get too long for your chamber, which is quite a bit longer than maximum trim length.
The only caveat I have ever seen to that, is anecdotally I always had trouble with consistency using the Lee collet die if they weren't all the same length.