If I'm not wrong, since a few updates .... you cannot choose a precise dry tires set in the presets but you need to choose them in the MFD pitstop board when on track.
In the preset the only choice for tyre replacement is DRY or WET
Not 100% sure but I think the automatic proposal will be a new still unused tyre set .... but you'll be able to choose another one if you prefer in a tactical decision ( very limited tyre sets allowed for example ).