'60 - '62 Frame and Rear Suspension

[1972RedNeck]

I have a couple of questions that I have been unable to find clear answers for lately. They all deal with '60 to '62 2wd frames and suspensions.

To start, they all have torsion bar front suspensions, correct?

And if they are the trailing are rear suspension, they have the "X" frame, correct? But what about the leaf sprung trucks? Did they still use the "X" frame?

Now for the the confusing part. Most all of the 1/2 tons I have been around have the trailing arm rear suspension - but I have seen a couple that are leaf sprung (and they both happened to be GMC's - coincidence?). I have also seen 3/4 ton trucks with trailing arms and leaf springs - but all the GMC's were leaf sprung.

So what was the deciding factor for whether or not the truck got leaves or coils? And are the frames the same between coil and leaf trucks?