I suspect that a lot of sellers would be glad for 700+, at least in my part of the country.
I see Ruger No.1's from 425-1000 depending on various points of view. I stay down in the 400-500 range myself, or move on for the next one.
One might look at some of the guns that have sold on various big internet auction sites for an idea of pricing. One has to bear in mind, prices vary around the country.
Some give a bit more for the No.1A AH iron sighted models over the longer sightless(irons) No.1B's. Same with the wood quality. Lately, I make no such distinctions, only see the action and change the rest in due time; caliber is not important, as it will be changed anyway.
Take a look at the local shops from time to time, look at the sold sections in the internet sites, and just ask around in your locality for pricing that moves product.
The No.1a and No.1b are different in barrel lengths, basically 22 versus 26; both are representative of a nice hunting styled rifle.