Unless I am mistaken, which is certainly possible, the only recent production Blackhawks that are medium framed, are the flattops. Even these are not the "same" frame, they are only similar in size.
If it is a standard Blackhawk of recent production, it will be one of the large frame guns if I am not mistaken. Would you mind clarifying exactly what Blackhawk you have? I was not aware that any of the medium frame guns were available with the Bisley grip? Once again, I could easily be wrong as I have not kept up with all of the changes in recent years to the Ruger lineup. But I am certainly curious.