The same records are in the March 1932 issue - although quoted in km/h rather than mph, which perhaps indicates that it was a list that emanated from the AIACR and which Motor Sport copied and then updated themselves. There is no equivalent list in any 1931 edition.
However, the Swiss Automobil Revue (as so often!) comes to the rescue. Page 3 of their issue #25/1932 of March 18th includes a list of records newly homologated by the AIACR, including all seven from 2000 kilometres to 4000 miles and all four timed ones from 6 hours to 48 hours, set at Montlhéry between November 28th and 30th by Chinetti, Pesato and Zehender using a 6-cylinder Alfa Romeo whose capacity was measured at 1752.6cc. Times (to hundredths of a second!), distances (to the metre) and speeds (to thousandths of a km/h) are quoted if you need them.
The 4000 mile record is also mentioned in the French paper L'Intransigeant, i/d December 1st 1931, p4. Le Figaro, same date, p7, goes into great detail - including all the previous record holders! Both available online on Gallica.