Hello Melissa
Short answer yes. People rarely used their Baptismal names and almost always used the shortened form. Because documents were hard to get, the Officiating Officer had no option but rely on the name presented by the persons involved. Often the Officers were English or Dutch and did not know how to spell the presented name anyway and would resort to a known or common or easy spelling. In the case of Johan/nes or John it was most commonly changed to Jan or Hans or even Hannes. Even as far back as late 1600's The only way to tell is if the other parties on the document has the same names. I have even seen a Janz. Accuracy was not paramount.
