From the various J/30's I've raced on I've seen that the 'new' interior layout (starboard quarterberth only) the battery switch is to port, in the locker under the sink. The 'old' layout (quarterberths on both sides) has the switch to starboard next to the cooler.
I believe all J/30's were factory finished. There were a number of options (teak & holly sole, for example).
