Good question! The Redline V-Twin line of products is new for Redline. I'm not convinced that it's anything more than marketing. Anyone know?
Hoist! 
I agree with Howie, I've used both, haven't noticed any difference between the two, but it good stuff!!! My dealer only carries the trans oil with Shock Proof now, so I'm now using it.
Shock ProofActing like a liquid grease, these unique lubricants contain a suspension of solid microscopic particles as an extreme pressure agent, offering a "best of both worlds" balance of low drag and superior protection for gear teeth Unique lubricant with solid microscopic particles offers low drag/high protection
Relatively low viscosity, yet cushions gear teeth under extreme pressure
Helps to prevent tooth breakage, resists throw-off
Avoid use with pumps, coolers, and filters as unique medium and affinity for metal can cause clogging
V-Twin Trans Oil with Shock ProofThis product dampens transmission noise (reducing the notorious shifting clunk found in these gearboxes), dramatically reduces temperature, provides thicker oil films between gear teeth and resists throw-off
For all aftermarket versions like Baker, JIMS, S&S, etc.
For all H-D® trans including with Evolution engines, Twin Cam engines, and latest 6-speed Cruise Drive
Same fluid as our unique Heavy ShockProof® Gear Oil Craig