From head of engineering thru all the video game eras at WMS even prior to Defender- Sorry but I do not remember us ever making an "oak" cocktail cabinet for any reason for any of our games. From the pictures, it appears to be pretty much the same as the cocktail cabinet we did produce but the production units were not "oak". It would have been too expensive to build with oak wood. My guess is someone "hand built this unit" .
Got the replacement glass top and original wood top back from the glass shop today, once I get it mounted I'll snap some pics with that in place.
Took the monitor out today and noticed that what I thought were wooden supports (the pieces that the monitor bolts to) were actually metal. My recollection from production Williams cabinets were that they would have been wooden, but I haven't had one for a couple years so maybe someone can confirm.
Still looking for an original boardset if anyone has one!