Probably Been Asked Before..But I Have To Hurry

[magwakeenercew2jh]

I'm building the '68/'71 C10 short bed, Fleet using the 71 frame.

I've got the opportunity to pick up a stepper bed if I move fast. But I don't know the year of the bed. So, I'd like to know what years (besides 67-72, of course) stepper beds fit on our frames,
if any, as a direct fit. Then, if I can, I'll try to figure out what year the bed is before I jump to the head of the line.

I'm keeping the Fleetside bed. But I'm in the middle of body work, so it would be nice to have the stepper bed to work on at the same time...use the same paint, etc. I'm really in love with step sides.

But I need to know if this one would be a fabrication nightmare, or a direct fit. And, if anyone knows any tricks on how to identify the year of the bed, I'd really appreciate the advice.
The guy is "selling it for a friend", so he's not going to be any help.

The Fleet bed is in decent shape. And, I know that Fleetsides are more popular. I had a nice one. But I can't make up my mind. Thanks.

Here's my current bed: