I agree with Jim...
Having owned an '82 3607 AC since 2003 - Fantastic boat. Alot of sweat equity in her (long list), and we have her just about the way we like her. Now nearing Pristine condition - in the middle of refurbing the flybridge with: Corian, new lighting, carpet, new Bristol on the teak, etc.
Wouldn't part with her for less than $80-75k. Like Jim, I know it's higher than market - she needs NOTHING, and market won't comp for the nice upgrades we've added. This is no "dog" - she comp's with boats 15 years younger, + with much more character if you like the wood furnished interior like we do.
If you are meticulous like I am, you'll end up investing one way or the other after a few project seasons. This is like therapy for me!
Ironically, I still have the itch for a 4207 model. I am liking the 15' beam, hard top option, with diesels. My wife says I am crazy after all my work. She's probably right.
I haven't put ours on the market, but for the right price, anything I own is for sale.
Good Luck with your search.