It really is difficult to determine what exactly transpired on the 3rd hole over time.
Even the Donald Ross drawing indicates existing "rough hollows" short and left of the green, so that could have been part of what the original hole description spoke of when it said, "the green is guarded in front by a deep grassy pit".
In either case, there is no existing evidence of any such feature.
It also appears that the original Hugh Wilson version had three large sand pits alternating left, right, left, almost down the length of the hole along the sides. Donald Ross called for pulling them tighter into the fairway, and adding a second one on the right up closer to the green, which would also provide protection for the 6th tee.
In reading his instructions, I did have to smile to learn that the "look" was important to these guys as well, much like today when he writes;
"Extension of Present Deep sand pit. Keep it rugged in appearance"
In any case, it looks as though over time the large, rugged, singular bunkers on each sides of the fairways shrunk considerably, and were formalized into sets of smaller bunkers.
Their distance from the main playing areas really keeps the hole from being as strategic as it could be, so although Ross had some good recommendations, there is no existing evidence that the bunkering schemes were ever brought closer to the lines of play.