The original compressor on your car was the 55-60 version which is different. The major difference is the two piece front bearing housing with its own carbon seal that is apparently not available and likely wouldn't work in the later compressors. The current seal may work in the first gen compressors but I haven't put it to the test yet.
Another major difference are the heads and valve plates which are not individually interchangeable between versions of compressors. Perhaps late version head and valve plate pairs will work on early compressors but I haven't tried that. Gasket sets for the early compressors are not available and those I have seen listed for the late version are no longer available. I would like to know how the rebuilders solved this issue.
Another difference is that all early versions had an oil pressure regulator that seems to have been eliminated at some time in the later version. Even that regulator had been changed during the early version production run.
I have not seen any early version compressors pictured in the ads for rebuilt compressors. The difference is obvious at the front of the compressor. It is possible no one will ever see the early version as a rebuilt.
Any corrections and added information to this post is welcome. Particularly regarding gaskets.