Neatlinetime dates incorrect

I am trying to use the new new Neatlinetime plugin on my previously created site. The site features a collection of photographs, for which the only known dates are either month and year or just year (May 1936 or 1936). The Neatlinetime plugin is plotting items at dates not at all related to their dc dates (January 1938 at Tue, 22 Apr 1975 04:00:00 GMT). I guess that my dates are not in a proper format that Neatlinetime can recognize, but since the dates appear on my item show pages, and since there are more than 600 items, I don't want to have to change the dates to a different format. Is there for Neatlinetime to convert my dates?