[78-L] Piano duo plays "Merry Widow" -- dates?

[Bryan Wright]

I have in front of me a fantastic 12-inch Columbia (blue label) of  
pianists Beryl Rubinstein and Arthur Loesser playing an Arabesque on  
tunes from Lehar's "Merry Widow." The disc is Columbia 71209-D  
(matrices XCO 28994-1 and XCO 28995-1). I've tried looking it up in  
several discographies I own with no luck and have spent a while  
scouring the internet but I can't find a reference to it anywhere.  
It's a brilliant performance and I'm very interested in knowing when  
and where it was recorded. Can anyone help?

Thanks in advance!
Bryan W.