By the late 70s the doors on inbound trains opened only on the right. The platform on the left was disused. Angled wooden walls had been built along the back of that platform; they were built over the platform of the old west streetcar loop; the loop was gone at that point, except for the lower part of the incline which was I think on fill between stone or concrete walls and still had the tracks https://bostonintransit.com/products/du ... ation-1982
, but from looking at some pictures just now I see that at least the platform roofs were still there. (Those roofs still exist, because they are part of the original station roof that that T saved and made into the Dudley bus station. The east streetcar loop had been turned into a bus loop. I remember looking out of the train at the buses. I only ever got off at Dudley once, the day Pope John Paul II came to town; the trains ran from FH to Dudley and stopped, I suppose so they wouldn't run in front of the cathedral during his mass there.
I am pretty sure there was a free transfer between inbound and outbound. I never used it, but the ped bridge was active, and if you look in the back left of this picture you can see stairs to the ped bridge going up from the inbound platform, clearly inside the turnstiles: https://bostonintransit.com/products/du ... south-1982
It is of course possible that those stairs were closed an other stairs came down outside the turnstiles, but I think that is very unlikely. In the original design, the trolley loops were in the paid perimeter, too, and transfers between modes were free, so there would be no reason to have two sets of stairs. The stairs we see are probably the only ones.
See this picture to see the walkway going over both inbound platforms and the inbound track: https://s3.amazonaws.com/nycsubway.org/ ... 110620.jpg
See these two pictures of the east loop as bus loop. You can see the newish turnstiles and walls that were put in well after original construction, I think replacing some kind of temporary barriers put up when there stopped being free transfers btwn the El and whatever vehicles used the loop at the time of the change. You can kind of see the stairs to the bridge coming down inside the turnstiles, and you cannot see any additional turnstiles:
right side of this picture https://bostonintransit.com/products/du ... round-1982
Left side of this picture https://bostonintransit.com/products/du ... -west-1982
Many years ago (1992) in the state transportation library I read the historic mitigation book made before the El was torn down. It had a bunch of pictures of the el as originally built and then at various phases of its history, and also some plans of stations, including Dudley, original and as later modified. It had the plans for the renovation of the bus loop that created the walls-fences I mentioned in those loop pictures. If that could be found, it would answer this question. But it is boxed up with the rest of the books from the state transportation library (right?) and anyway even if it weren't the library would be closed.