These are the skins using the updated source files found at AmbientImpactDesign's website for Barney Calhoun. There is a difference from Valve's HD pack. The hands are clearer, aren't as pale, and have a higher poly count.
Find out how I made this at my tutorial on
Find Ambient Impact at http://ambientimpact.hl-improvement.com/
Just slap this into your models folder of any Half-Life game.
C:\Program Files\Steam\steamapps*your name*\half-life\valve\models
C:\Valve\Program Files\Steam\steamapps*your name*\half-life\valve\models