In the 5.5" barrel SBH pictured above, the grip frame is the same size as the Blackhawk above BUT it's blued steel instead of black-anodized aluminum.
SBHs never ship with aluminum grip frames. Also, I seem to recall the ejector rod housing is blue steel vs. aluminum but I'm not certain.
All SBHs with barrels longer than 5.5" have the larger grip size (in steel, at least on New Models...a few Old Model SBHs had brass grip frames). The larger grip size generally has the "Dragoon" or "Squareback" trigger guard, 'cept for the Hunter's which is round (yet otherwise the same large size as the SBH Dragoon).
SBHs with the smaller steel grip frame also come in 4.68" barrels.