Be prepared to deal with the fact that if you bring a boat that has been in fresh all its working life into a salt water environment, you could have rapid and destructive failures of some gear.
I have the original 34 year old rigging
(which I inspect yearly) on my 1973 never seen salt 33 footer, plus a variety of original thruhulls (I replaced the seacocks/ball valves from the original "garden type" gate valves, however). I also have raw water cooling and a 180F thermostat for the Atomic 4. Were I to go into salt, I would have to immediately consider a standing rigging
change, because I'm going to do it "just because" in a couple of years for fresh water anyway. I would have to get the brass off the boat in certain areas and pop for bronze or Marelon. I would have to retrofit for FWC on the engine, because 30 year old Atomic 4s don't want yearly acidic flushes. Did I mention I'd need a new thermostat?
Lots to consider here that to my mind wipe out the premium...unless of course you are KEEPING the freshwater Bristol in fresh water. Then it's whatever the market will bear.
You would be amazed at how many really old FG production boats are still in use here on the Great Lakes. Part of that is the absence of salt.