I don't think so personally. Duckweed floats, as you probably know by now, and the inlet to your filter is underwater (I hope! ). So unless the suction of your filter is great enough to cause a small whirlpool then it shouldn't really be a problem.
I'm going to say no aswell, i'm running a fluval 304 and got duuckweed now, sure it will go into the jet stream (if your jets on top of the water) but it comes back up pretty frickon quickly. if it does go to the filter then you know you'll have a problem, as said previously you wont find out until you actually do it.