i-beams

Does anyone know how to tell the difference between a Forged I-beam and a Cast I-beam? I know that the pre-89 years were more likely to have the Forged beams than the post-89 years, but beyond that I am kinda in the dark.

I'm in the process of trying to decide where to cut and turn the i-beams. I use the truck mostly for driving, and the occasional weekend trip to the local ORV park. I've seen a lot of people cut and turn them at the ball joints, or they cut them in the middle of the beam. What I'm wondering...