There are no plans for No.2, as they built the greens in the field. As-builts? Haven't heard of any. I'd guess they'd have ample photos of the greens in their early years, especially considering the PGA was held there after they converted to turf.
From the Whitten's article:
Ross lived in Pinehurst … when… he refashioned the No. 2 course… Ross would walk the layout nearly every day, conjuring up another concept, another contour, another strategy. Maples would make it happen, sometimes massaging the final shape and flow of a green for a full week, using teams of mules with improvised wooden drags to float out the final contours from the native sand. They completed the course in time for the 1936 PGA Championship. Maples' oldest son, Ellis… observed the work as a teenager. He confirmed to reporters in 1960 that Pinehurst No. 2 was done freehand. "They didn't have a single blueprint," he said. "They did it all from their head."
Ron Whitten, Donald Ross Wouldn’t Recognize these Greens, Golf Digest, June, 2005