Engelhard rarity. Last 10oz Plainville MA bar?

This might be the last 10oz stamped bar minted at the Plainville MA refinery.

AllEngelhard.com shows this 12th series bar's serial number as the highest in the series.

From AllEngelhard- " 12th series Variety “A” in ‘P’ serial prefix transitional piece, last of the ‘P’ series run, less frequently seen. This serial number run was shared with 10th and 11th ‘P’ series bars as well as 100oz ‘P’ series. "

I have an email from AllEngelhard staff stating they do not know of any higher serial.

Being the First or the Last of any production run makes a precious metal issue very rare.

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