I think you can go wither way on the tires. But your gonna get ground down on price and/or have to discount the cost of a set of tires.
I personally always have a bike I sell be as ready as possible. Most people want a bike that they can buy and ride, some people don't care though. I got a buddy likes to buy the beaters, but he buys em super cheap.
I guess it depends if you want a fast sell for a low price, or if you want top dollar you can hold out and clean/prep it for top dollar.
How much you got in it? StreetBikeMike