I just recently replaced this exact spring on my truck as well. However, it didn't help with the clutch return feel as I had hoped. When I let off the pedal, it doesn't travel back up smoothly. In other words, the pressure it exerts back up is non linear. If I release the pressure on the clutch i expect it to slowly find the friction point, instead its more like an all or nothing grab.
Is this a problem with the clutch itself? I noticed that there is another, horizontal spring at the base of the clutch pedal that is fairly rusted. I can't find the part number for it though.
Sorry, I don't have a picture at the moment. I'll post one as soon as I can to help give you an idea of what I'm talking about.