I doubt it would cause any issues, but if it is a vacuum leak, it could cause a lean condition or KR at the top end. It'* more of a hint that something isn't quite perfect. It'* possible it could be a MAP problem, but that would seem to affect it at full boost, too.
No problems at full boost (or full boost as far as stock goes..heh) The car was running really lean when I had the vac lines rotting, however that problem seems to have corrected itself with the replaced lines. Unfortunately finding a minor vac leak wont be easy. I wont worry about it for now as its not a major issue.
Once warmed up all is well in the world. Keeping in mind that we have like mentioned confirmed our gauges to be questionable reference at best.. it'* my theory that GM intended the needle to never fully hit bottom or top, but merely stay within the range the whole time.