Dunno. Maybe the cabinet and table were actual boardroom furniture painted to match the set color scheme. Pretty clear from this screenshot that the table has a removable section. http://tos.trekcore.com/hd/albums/1x03hd/wherenomanhasgonebeforehd351.jpg
I took another pass at fixing a couple of your criticisms - the bridge railings and positioning of the table in the briefing room. On the latter, the position of the table doesn't matter as much to me since furniture in the sets was usually moved around as needed for shot composition. In fact, my suspicion is the table was turned 90° from its briefing room orientation for the shots as the rec room. For the columns, I'm only working with Microsoft Paint and the Windows Photos app, so the tech is rather limited for what I can do. Based on the screencaps for WNMHGB, the columns look close enough for me that I'm satisfied.
Also, if you decided to not use the drop out portion, fixing the bottom and refinishing the top wouldn't be that hard to do.
Yes, I intimated that possibility in my original post in blssdwlf's thread. The cut just seem too clean and the spacing too tight for an after-the-fact modification to me. YMMV. By the time we see the table in Charlie X, the top has been "resurfaced." Compare http://tos.trekcore.com/hd/albums/1x03hd/wherenomanhasgonebeforehd002.jpg with http://tos.trekcore.com/hd/albums/1x02hd/charliexhd098.jpg
Has anyone ever commented on the patterned wall paper above the chair rail? It adds texture and interest to the room.
In the briefing lounge? I think it’s smoked glass, similar to the panels in the transporter chamber. They’re backlit and the lights are potted up and down throughout the scene. It’s particularly noticeable when fast-forwarding through “The Cage.”