Ring blow by amount is very small when ring sealing is good regardless of the ring gap. The bigger the gap the more power loss, and this may be exaggerated in model size engine because the gap relative to the cylinder volume is large. If it bothers you replace it. I hope to actually investigate this but I have no idea how I would do a controlled experiment for something like that. I just checked some new parts for the Magnum 61 four stroke and measured .003" and the bore is just under 1". I also checked an Enya 46-4C with low time at .004".

Like Jens says, unless the engine is not running correctly I wouldn't bother. It is after all a model engine.