Attribute decorate existing classes at runtime / Run with no decoration.

[AnudeepGarge]

I have the following schema in my existing project.

[Serializable]
public class Message {
public virtual string Type {get; set;}
}
[Serializable]
class ByteMessage : Message {
public byte[] Prop2 {get;set;}
}

public class StringMessage : Message {
public string Prop3 {get; set;}
}
and 1000 of classes like this.

Currently using BinaryFormatter successfully, but lately I am seeing lot of performance issues and came across this wonderful library.
Is there a way I can continue without decorating [ZeroFormattable] and [Index] attribute?
What would be the best way to migrate all DTO types efficiently?
Thank you.