Rusty 1972 truck for free

[rusty72]

I am new to this forum. I have always loved the 67-72 trucks so when I was offered a 72 for free I couldn't say no The truck is in really rough shape. The truck came with no box so I was thinking of shortening the frame and ordering a new short box. I also came across a picture a 1972 with a newer 90's style box, does anyone know if this is a common swap? From the picture it looks like the body lines on the new box lines up with the 72 cab?

Here is a picture of my new truck


Here is a picture of a box on my truck I would like to use