That's kind of on the edge. It's 2.7 thou off - a tad less than 1% (0.79%) larger. Given that a router runs between 12K and 24K RPM, even a small imbalance get's magnified. You might be able to wrap the shaft with 1.35 thou thick something - maybe two turns of aluminum foil but the trick is keeping it on the shaft when putting the bearing on. Anything that thin isn't going to be very stiff. Personally, I'd probably try it bare but I can't recommend others do it.