Yes. If you want to redshirt the freshman with the most potential to improve, but not the lowest rated freshman that you will sign (and you do!), then you want to inform of redshirt to be sure he will accept it. JuCo players need to be informed of redshirt or they will almost always see a big WE drop.
If you are certain that the player with the most potential to improve will also be your lowest rated freshman, then informing is probably a waste. Although, every now and then your lowest rated freshman will have a slight drop in WE when the redshirt is applied.