Some of the Freedoms were built by TPI (what Cam is calling Pearson), and some were built by Freedom at their own plant. It depends on the year of the boat. The earlier boats were built at TPI, and the latter at Freedom. I can't remember when the move was made. Regardless, I am unaware of any systemic problem with any model. Freedoms were well-built boats, and the potential for problems with cored hulls were known when these boats were built, and they were built with minimizing the potential for such problems. I know personally the plant manager who built the large majority of the Freedoms (Paul Dennis), and he is a remarkable craftsman who takes quality very VERY seriously.
Pay particular attention to the below-the-waterline through hulls and areas around them. If the moisture meter spikes in those areas as compared with others, then there MIGHT be a problem. I stress "might" because moisture meters are notoriously troublesome in terms of getting accurate readings. They are most useful for comparing one area of the boat to another, not absolutes. If the surveyor tells you that the hull or deck is "wet" because his moisture meter hit a certain number, be skeptical. If he tells you he suspects an area is wet because it read higher than some other area on the hull, that's something I would consider more seriously. But even that is not necessarily a deal killer. It depends on how far the penetration goes. It is an eminently repairable situation frankly, assuming the moisture did not migrate too far (and Freedoms were cored in "patches" to limit the extent of water migration in the event water did get into the coring somewhere). Depending on the year of your boat, etc., it may very well be that Freedom pre-routed out the hull around all through hulls, so it shouldn't be an issue (this was done on most boats, but not on some of the earlier ones). I know about this pretty first hand, as we had hull number 2 of the Freedom 45, and we pulled our through hulls, had the coring routed out and backfilled with epoxy. It wasn't the cheapest repair ever done, but it was far from the most expensive either.
I think these are great boats, and it was with a heavy heart that we sold ours and moved on to something else. I'll tell you, there are days when I question the wisdom of our move, not because we don't like our new boat, because so far we love her, but just because I really loved that Freedom.
In terms of your question about surveyors, I sort of addressed this above already. The short of it is yes, surveyors can do a pretty good job of detecting hull moisture in cored hulls. Be sure the surveyor sounds the hull, and doesn't rely only on a moisture meter (I'm very skeptical of those things). Also, I would be sure to find a surveyor who has a lot of experience with cored hulls. Others will tell you that any surveyor will do because just about every boat has a cored deck, so all surveyors are used to looking for wet coring. There is some truth to this, but hulls are a little bit different, just by their nature, and there are few boats that have cored hulls, so in my opinion it's best to find a person with experience evaluating those.
If you have specific questions about the boat you are looking at, give some thought to contacting Paul Dennis. He now has his own small yard in Warren, Rhode Island, and he specializes in (surprise, surprise) Freedoms. His yard is called Warren River Boatworks. If you call him, tell him I referred you.
Hope this helps.