It might imply that the dating systems have some connection. It's established by now that there was trade between the New World and the Old World before Leif Ericson, and that was between South America and Egypt. Something made someone decide that the first day of the new year was a particular day. The fact of the solstices being almost but not exactly at the end and midpoint of the calendar year is a legitimate puzzle. The solstices would have to be part of the Mayan calendar, so there may lie the connection that makes for the numerical coincidence.