Leamas,
The only way to tell is by watching the horse get over different dirt tracks. There is really no way to verify what you are looking for before they run.
There is strong data(see TG, Beyer,Rags) which show that horses coming from certain circuits, like Delaware Park, Philadelphia Park, do NOT reproduce their ridiculous big figs when shipping to New York, for example.
Until a few years ago, horses with competitive TG figs, shipping from Churchill to Saratoga did extremely poorly as did the 3 trainers who raced many of them.
The two examples cited may have little to do with the different dirt surfaces themselves but rather with the permissiveness of some tracks to look the other way re medications.
Mike