manual vs Automatic crankshaft

No they are not the same at all. The manual transmission crankshafts are drilled much deeper to accept a bronze pilot bushing. The automatic crankshafts are not drilled near as deep. They usually require you to trim about 3/4" off the end of the input shaft and also require a different style pilot bearing that presses into the crankshaft register. Normally, forged cranks are drilled for the pilot bushing and cast cranks are not. Also, the cast cranks generally cannot be drilled because you will run into the oil passage as the crank is made completely differently from the forged crank. That's why the input shaft has to be trimmed and the different style pilot bearing must be used.
Rusty, I have seen plenty of cast cranks that have pilot busing from the factory, it does not make sense the factory would make two cranks for the different trans.
For the op it will be hit or miss on the engine you bought.
I have a 72 340 in my duster, cast crank, it is drilled for a pilot bushing.
I also have another 72 cast crank 340 in my building that is not drilled.
I also have a 360 cast crank that has a pilot bushing, and a mag 360 that came out of an auto, but the crank was drilled for a bushing.
And a 74 318 that is not drilled.
70 340 with the bushing, but it came out of a 4-speed car, I parted out.