The LaRocco PRII when it first came out had the AD8620 (if memory serves me right). Then they discovered that the AD744 sounded better at the risk of some noise w/ highly efficient IEM's. So the gain was reduced for those users at the time the AD8620 was replaced w/ the AD744.
The PR2 has always had the AD744 and it was redesigned to have an attenuator to help those who have IEM's. The attenuator is supposed to sound better than a gain switch or so the experts say.
Although IMO the Reference and the Supermicro IV sound better than the LaRocco PRII MkII all three could take a long time to arrive. Plus the respective vendors do not have very good communication skills. I personally would then go w/ an SR71 or if you are willing to roll op-amps the iBasso D1.
Skylab has my modded D1 and should provide some feedback in the next few days.