In season 5's Home, Dickie's bedroom made an appearance. However judging from the photo above, outside the door you can see staircases. Does that mean that Dickie's bedroom was downstairs?
It also appears that Dickie has 2 beds in his room- one regular as the top photo and the other as a bunk bed. I don't think he shared his room with Elizabeth though, since there's no girlie things in there. I believe that under his bunk bed, rather than another bed it looked like a desk. I've seen those around time to time with a desk underneath the bed, so it's not unusual.
Another puzzling thing about Dickie's room is that there seem to be a mini-hallway with a door. I can understand a closet but a door? Did Dickie had his own bathroom? Or his own entry door, where he could come and go as he pleased?
Dickie's room appeared briefly again in season 8's Annihilated when Elliot went in to check on him sleeping. Judging from the door behind Elliot (as well as knowing that he had just checked in on Kathleen & Elizabeth earlier), Dickie's room's now upstairs rather than downstairs with it's own door from season 5.
I do strongly believe that Dickie always had his own room, never shared (except for maybe Elizabeth when they were babies) while Maureen?, Kathleen, and Elizabeth played musical bedrooms. Eli also had his own room.