It's a vintage "old pour" Johnson Matthey bar. They are quite collectible. As to why no fineness stamp I have no clue. Maybe it was an internal bar made for an employee? I wonder if the no finesse stamp might add to the value to a collector if you also have it tested for buying confidence. I would research this further and try to contact dealers that specialize in them.
Here's ebay listings
http://www.ebay.com/sch/i.html?_nkw...ilver&_pgn=1
Here's ebay listings
http://www.ebay.com/sch/i.html?_nkw...ilver&_pgn=1





















