This is not a hard swap to do, I did it back in October. You cannot swap just the pedals, you have to use the bracket under the dash as well.
If you are planning to go with manual clutch linkage, it is easier to just buy the z-bar bracket than to remove the one from the donor truck. GM sells them for about 13-15 bucks. American Classic Trucks
sells them for $8.00. As far as drilling holes in your frame to mount it, you shouldn't have to. The holes should already be there.
Also, i would buy a new clutch fork as well. I thought that the one i had was fine, but a month after the swap the clutch adjuster rod that pushes into a recess in the clutch fork pushed the whole way through and i lost all of my clutch adjustment about 50 miles from civilization. The are about $13.00 from LMC.