If, as you say, the handlebar rotates freely and does not bind, you should be fine; over time, you may lose some paint from the top of the headtube but you wouldn't see that anyways.
For what it's worth, Deda in some of their technical drawings show a headset gap of 0.8mm; if you wanted to, you could add a 0.25 or 0.5mm headset shim/microspacer.