Yes, the top cap should come off easily once the top nut is removed. Then the stem and all the spacers should slide off in sequence once the stem clamp screws are loosened. After that the upper bearing and centering cone, allowing the fork to drop out of the frame.
I doubt rust is holding the top cap on, but just in case, put a small screwdriver under it at the stem's slot and give it a gentle nudge.
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