Mark,
To further your point, I'm not 100% sure ours are/were the same. The back of mine was distinctly different than the one you posted in the scan. If you look at the "bigger" mark on the bottom center, you will see yours has a distinctive scratch to the left of it. Also, to the right of that mark, your line seems to be missing or worn away. Both of those marks do not appear on the back scan I retained of the one I had.
