[mweishaa]

Oops, thought I put that in the post.. sorry. 1964 GMC, longbed stepside.
I think they are original. I didn't replace them, and everything else seemed to be original when I got it. It's a 3/4 ton, if that matters.

Now that I think about it, the two shorter sills in the middle, that just attach to the wood, are almost touching the frame. So I couldn't drop it.
The cross sills I got were from a fleetside, so I'm wondering if the original ones had an exra spacer on them, like that one in the front.