Ramius, given that liferafts are required (besides just good offshore common sense) - yes, it would have been quite negligent not to have one onboard.
Its easier to find a place for a trunk that big on a motorboat, but on a 38ft sailboat there arent too many good places for it on deck. Again... I know it ~can~ be done, it just isnt common. All Im saying is that its not necessarily fair to allege some kind of negligence for not having one.
Other pics on site show that the raft case is directly athwartships the radar mast, suggesting that in a roll the raft may have fouled on the mast. Not saying that it's necessarily a bad location for the raft, since hardly anyone expects their boat to turtle, but food for thought.
Pics on the TAMUG site clearly show a common case mount - the life raft mounted on the starboard aft quarter stanchions, outside the lifelines. Immediately inboard the lines is the radar mast.