The dash number is the version, often it has no discernable changes. B110 originally came with LT-135-13. Some of the later versions may have different ears for use on a Mazda or Isuzu or somesuch

The exact interchange is as follows (USA models, probably same/similar in other countries). Basically if it's a Datsun 35A, it'll work. In USA most Datsuns used 50A units which are physically bigger
* B110 1970-1973
* B120 1971-1985
* B210 1974 standard duty
* 510 1968-early 1971
* 521 1969-early 1971
* 620 1973-1979

The best one to use is the LR135 from 1979-1989, it is exactly the same size and has internal regulator. Just unplug the existing regulator and jumper two wires. See LR135 for more details