others with more knowledge of the hunter design will surly know more about the particular boat than I do, but still, here is my opinion...
there may be no manual valves in the system.... you never know how it was designed or modified....
a well installed system would have an automatic check valve and a manual valve, but I have seen installs where there is only a manual valve in the city water intake line, others with only an automatic check valve, and still others where there is no valve at all, and the only way for the onboard pressure system to function is to cap the city water connection so the onboard pressure does not push water back out the city water connection.
if you have never used the "city water" system before it would be a good idea to turn on the faucet in the galley sink before turning on the spigot on the dock....
this will give the water an easy place to escape to while you are getting aboard, just in case there is a broken line somewhere... after you board the boat you can shut the water off at the sink and then check for leaks.
as for the need for a manual valve in the city water system... if it is installed, it needs to be at the intake.... a shut off on the boat is convenient, BUT it does not NEED one as you do have the dock spigot less than 50ft away to shut the water off.
when you leave the boat unattended, the "city water" should always be shut off... otherwise, in the event of a line bursting inside the boat, the city water pressure will secretly run unchecked into the boat until the hull fills and sinks....