Storyteller,
Thank you for the inquiry.
because of certain licensing agreements between Mapmedia and their charts sources, Mapmedia is restricted from displaying the chart data itself online. as you have found, they can depict the approximate coverage map/area's, but cannot display the data itself.
as such my suggestion would be to contact the Furuno technical support team (410-479-4420), provide them with the 9 digit part number of the chart that you are interested in, provide them with the latitude & longitude of the area that you'd like to preview, and provide them with an email address. They may be able to provide an actual screen shot or two of the chart taken in the area that you've requested.