(Apologies for reviving this thread)
I just stumbled across this post. Because it is about the particular make and model of boats that are of interest to me, and there may be others that follow me, I thought I'd post what I know.
The Pearson 34 III was manufactured by Pearson Yachts from 1989-1991, and by CAL-Pearson in 1997. It differed from earlier Pearson 34s in that it had a balsa-cored hull (above and below the waterline), as well as balsa-cored deck. They have a large head with a separate shower stall, to starboard at the bottom of the companionway. In general, down below they have an open floor plan, much like a P-31, or CAL 33. Sleeping accommodations are in the V berth, the salon, and a rear quarter berth behind the galley. The transom has a "hatch" which is attached to the boarding ladder. Opening the "hatch," opens the gate to the cockpit, and lowers the ladder. Many of them (all?) had a self tacking jib that required a track mounted on the foredeck. The yanmar diesel is mounted under the companionway ladder.
The 1986 - 1989 Pearson 36 II was built by Pearson Yachts. I think of this boat as a single head version of the Pearson 39. The interior is HUGE. This boat has a separate cabin to starboard, and the head to port, both at the base of the companionway. In order to create more space in the rear cabin, the motor was moved forward, and sits under the sink in the galley, with access from under the starboard setee. There is a Nav station with a swing out stool to port. The non-dropleaf table in the salon is mounted to the keel stepped mast. The entire table, however, can be dropped to convert to a double bed by simply unscrewing a thumbscrew, and removing (or lowering?) the pedestal that the table is mounted to. In 1989 Pearson added a sugar scoop / walk through transom, removed the swing out stool, and changed to a dropleaf table, and called it the Pearson 38. The Pearson 36 did not have a balsa cored hull. I'm not sure about the Pearson 38 though.
For more info, look at Pearson Information site
I hope that someone finds this useful.