I replaced my standard fairlead with a stainless-steel lined one. The screws were spaced one inch apart. Maybe the pulley (block) mounting has the same spacing.
I have a 1971, and it has a pulley/block. It works as it should, and assuming yours works as well, I would not replace it. Likely you would have to drill new holes and fill old ones if you did.
My guess is that the block was replaced by a fair lead cost reasons.