I've been following this thread, wondering if ours potentially could have an issue as well. We have not had a chance to use the convection part of the micro yet, so I don't know what it does or doesn't do at this point.
However, on the 3741FK model, the convection/micro is in the red square highlighted below, and there is NO vent there on the outside of the slide. I have not had a chance to look on top of the slide, but I'm assuming that there's not a vent there either.
It appears that all models are not vented...