1953-D Franklin Half Dollar.. Brockage? Struck-Through Fragment?

I took these photos over two years ago. I have better equipment now, so if someone here requires better photos, it is certainly available.

This was in a dealer's melt bin.. (?what?)



There are two pieces of debris. The most obvious piece, of course, is a fragment of another Franklin half dollar; it is easy to recognize the mirror image of an "ER" from "LIBERTY" as it appears on the obverse of every Franklin half.




So.. we have another piece of struck-through debris. Long story short: I assumed a Franklin fragment. My sleuthing led to another Franklin fragment, reverse-facing:




In case you cannot tell, I outlined the border of each fragment in the image so I could compare them to a scaled HD image of a Franklin for confirmation. In order to do this with accuracy, I first had to flip the crop; each of the fragments will manifest on my coin as a mirror-image of what actually struck it.

Here is an illustration, with the struck-through-outlined portion mirrored:



What happened here as it appears to me: fragments of a previously-struck Franklin half dollar somehow retained within the coining presses became simultaneously stuck onto a reverse die just before striking this coin. Does this seem accurate? Does anyone have additional input?