It appears that FCP correctly converts the Date Modified field (head table) from local time to GMT on export, but it is not correct for the Date Created field.
When I create a new font, the local time is written to Date Created rather than converting to GMT (as indicated in the 1.8.3 spec). When the field is read, it is correspondingly not converted from GMT to local time. This is only apparent on a dump of the font, since all appears AOK from within FCP.
-Clint Goss