Was it mailed with a postage stamp or was postage paid by some other way. If postage paid by some other means than a postage stamp then there might be a way to trace it. The post office would have to be paid some how for postage if the permit was obtained at the Post Office or otherwise mailed under an existing permit. They don’t do that for free. If a postage machine was used I don’t know if that’s traceable.
“Inspired by the Stewart/Colbert Sanity Rally today, I’ll play along...
Re? A drop of golden sun?”
Why not?
Me, a name, I call myself.