UDT/F, your grasp of naval history and designations is pretty shaky. Yes, US Navy ships have a contract number - it has nothing to do with the hull number. US Navy ships have a hull number which designates the type of ship (CV is a carrier, DD is a Destroyer, CA is a Cruiser, etc...) with a number sequence which applies only to that type of ship.
NCC originally meant nothing - it was derived from US civil aircraft registration (N was the US national designator and C meant it was a civilian aircraft). 1701, was actually the street address of one of the crew on the show. A photo of Jefferies 1935 Waco aircraft is reproduced in A Star Trek Sketchbook and definitely is not 1701, but a 5-digit number (don't have access to the book right now, so I can't quote the exact number). The second "C" was added for æsthetic reasons.
The explanation of NCC as "Naval Construction Contract" originates with Franz Joseph Designs' Star Fleet Technical Manual, and Naval Contract Code with later fannish works.
The closest one can come to a canon meaning for Federation-era NCC numbers is the informal system used by the Star Trek art department during TNG and DS9. NCC is a Starfleet active service vessel. NX is a Starfleet experimental or prototype vessel. Other Federation vessels also begin with "N" - NFT is a Federation civilian transport, NAR is a Federation civilian science vessel, NSP is a Vulcan registry, and so on. the "CC" would appear officially to be a Federation designator for an active service Starfleet ship.