I saw this one on eBay and found it rather interesting given the lack to stamped serial number on the back and very shinny case.

It got me thinking whether this was an early prototype or given the poorly engraved number on the back whether it was actually an issued watch - my rationale being that some of the 3464 Panerai from this era were also engraved like this.

I rather like it.

http://www.ebay.co.uk/itm/2823118494...%3AMEBIDX%3AIT

As for the shiny case - poss a nickel re-plate.