Hello AcaCandy,
Let me put on my green makeup and my Vulcan ears. We have a manifest entry for a binocular with a serial number. The entry does not describe the binocular beyond a value of $10, a tad low for a 7x50, in 1947. and a serial number. You have a binocular with faked or altered prism covers, with the same number. You have an American style binocular, which probably should not have had duty imposted. It is not impossible that the engraving was made to match the manifest, some time after 1947, in the States.
There are all sorts of of other scenarios, which would make sense.
Happy bird watching,
Arthur