wild-b, Yes, that being a frame from last year makes sense. They just haven't moved on to it, to clean it up yet.
With the higher humidity levels now, in NE, it will show as white. As far as venting goes, I use a lot of slatted
racks, but also have normal 3/8 or 3/4" bottom entrances. A top entrance wouldn't hurt tho in NE. Some drill a
hole in the top box, use an inch shim, inner cover, or wood shim sticks to prop up the cover.