Marco is correct regarding GEDCOM.
A SOURCE and its corresponding SOURCE_PUBLICATION_FACTS are the correct places for dates of publication of a newspaper article. From a GEDCOM view a SOURCE_CITATION is used to identify a specific place in that source.
From the standpoint of FTM the basic source entry dialog/screen has three fields 1) Publisher Name 2) Publisher Location 3) Publish Date. FTM makes a mess of the SOURCE_RECORD in the GEDCOM when you output a source made with a template by putting everything in a NOTE.
Anyway, If you are entering a publication date for a newspaper as a separate field in the AMT citation, which is ok from a data entry standpoint, when a GEDCOM is created the date along with any other "publisher information" should be formated to follow publisher citation pattern based on any one of the well known standards like "Chicago, Evidence Explained etc.
GEDCOM does not have a field for date and does not need one. The database within FTM and AMT can have separate fields this is ok as well. The only time we care about GEDCOM is if you are creating one and you must know where to put the data to make a well formed record.
The same is true for SYNC. They should have distinct fields in their DataBases and if they do not the communication protocal should know what is needed to consistantly make the date data and other data go back and forth without data loss.
This is a bug that can be fixed since the interface and products come from the same company.