I'm looking at buying a truck that has the C notch, the shocks are fully extended, I can see the entire shock rod, no compression on it at all, is this correct, or does it need longer shocks?

 

Really don't know, but I just can't imagine all the travel in a lowered trucks suspension coming from compression. I think a lot of lowering kits have shock extenders. Maybe these were omitted on this truck? Hopefully someone more experienced with these chimes in...

 

I would venture to guess it will need longer shocks. I would have to guess the shocks are for a larger amount of drop than what the truck has. The C-notch should not have any affect on your shocks though.