Might be a touch high on the estimation for the 2 wheel drive. $3500-4000 might be a little more realistic. Can't speak for the MFD,they're just not easy to find on an 1850 so that might be one of those things that's worth what one person is willing to pay and another one is willing to take.
I gave $5600 for this one at an auction near St Johns 15 years or so ago. It was a one owner with 4600 hours. I don't think they've come up in value since then for sure.