is a 75 3/4 ton frame the same as a 84 1/2 ton

i want to get this frame to build my SFBD frame incase i make an opps or mess something up. this will be my first frame build so i would feel more comfortable learning on this frame rather then F-ing up the original frame. i think ive read some where that the frames are the same just the componets are different. correct me if im wrong.

anybody?

Not really sure hwat the difference is but the GM parts catalog shows 73-78 as the same and 79-84 as the same. Im pretty sure all the body mounting points are the same.