She's spayed so it doesn't really make a bit of difference if she's registered or not. Her sire and dam aren't doing the retrieving. Therefore, the only question (and a big one) would be what is the definition of finished. At the age of around 14 months all four of my dogs (see signature) were FF, CC, running multiple marks and running basic cold blinds. By no means would I have considered them finished...at that time. I would never have taken just $2000 for any of them.
Since this dog has already been hunting (experienced) that's a plus and she is only four years old which is fairly young (if she has no health issues....hips, etc.). Anyone interested should find out in person what finished means and if you are only going to hunt a few times a year.....forget about it.
Is she steady? quiet in the blind? those make a huge difference. Any good, young started (not running cold blnds yet) dog will run $1000-2000....and definition of "good" varies considerably. She might be a terrific deal. The only way to find out would be to check her out "up close" and in person.
My oldest will be 13 in June. Last season she picked up a limit on opening day.
If this four year old would hunt until she is 10 years old, the $2000 would amount to a little over $300 per season (not including other expenses). That's not a lot for a dog. Then again duck dogs and hunting do not make for an inexpensive "habit".
In the end, she could very well be worth $2000.