For a No. 6 dial it is indeed hard to see. For the No.4 and No. 5 dials usually the type is very easily seen.
But a No. 6 dial is easily recognized by its construction. What is more interesting at this point is indeed the date. When dials were replaced in the 60s, No. 6D dials were indeed equipped with the closed finger wheel, and I have also seen that a 6A dial was over-painted white to look like a 6D.
Those are the reasons I asked.
The number card is not from the 1950s, it's an early 60s card, so I think the solid window FW was there when installed.
PS:
Ok, we cross-posted, and you added a picture. Very good, the dial is the original. So, the the finger wheel was installed in the early 60s when that number card was installed. The exchange names were dropped not long before the switch to ANC. It may be possible to find newspapers with Bell System ads that announced when this happened. The central office name was FOrest.