Funny you mention that. I'm going to be rebuilding my friend's 52 F-1 that he lost in a garage fire. I'll need a donor truck to start with and have been searching all over for a good candidate. 51 and 52 are similar with only having a few differences.
Although I've been looking at project trucks, the restored ones do pop up un the search. I've seen very good driving examples anywhere from $12k on up. I will say that a correctly restored one commands a good price ($20k-$30k easy) and of course you have the dealers and their dreams, but they just don't have the popularity of the Chevrolet AD trucks and also, being a two year body style, there was a reason for that: appeal. And parts availability is tricky. The 1950 and early Ford trucks looked better, and then the 53 Fords brought the famous F-100 styling into the picture which trumped early models.
I will add that the fiberglass fenders definitely devalue the truck. Paperwork is a good thing, obviously, but it's the poularity/year of the truck that actually sets the price point on this one versus the restoration. Feel free to email me or PM me if you want! Hope that confused you enough!
Cheers
Dave