It lists sessions beginning 20 July 1959 at which Rubinstein, with the LSO and Krips, set down Kk.453, 466 and 488. They are all labelled "unissued". Since the Gray catalogue is not brand new, this could have changed in the meantime, but I suspect these attempts will remain buried, since the same 3 concertos plus K467 were set down in New York with Wallenstein in March 1961 with excellent results.
Rubinstein did make K491 with Krips in New York in April 1958 and this was issued, though Krips seems afraid to be himself and the four with Wallenstein have better dialogue with the orchestra.
All this is marginal, of course, to your excellent comments on the Chopin disc under review.
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