Being that no one's answering this, I'll throw in my opinion. I never remove the pulley on 850s just to replace T-belts SO I don't ever try moving the crank as you've done to know just how "normal" that may or may not be. For all I know, maybe it's not un-common although it doesn't "sound" good from your description.
I do know that if the trust bearing is too worn (too much freeplay) AND it begins to be a problem (like noise or seals leaking, not fixed for long by just replacing the seal) then it's a big job as the crackshaft must be at least slightly moved to replace the thrust bearing (part of a main bearing).

I'd say that for now, if you're having no problems, I'd do nothing.