sounds like they plan to print the maps on a desktop printer. Normally when producing something like this you'd make the document about 5 mm (1/5 inch) larger than the final format, add some crop marks and cut it to size after printing. Professionel printing would also mean being able to not worry about the amount of black on the page, although with deep black you should probably add a coating afterwards to protect the print from fingerprints.
But looking good - congrats on the commision