That's as may be, but the US certainly had to be aware of the T-34 (sloped armor, diesel engine, higher muzzle velocity, slightly faster and with double the range of the Sherman) by late '41 or early '42. Should have given us some vague idea that the Germans were going to do their damndest to build something better.
At the end of 1942 the Soviets sent a T-34 and a KV-1
to the United States for familiarization with their designs.
I have never read the Report from the Aberdeen proving grounds that did the testing, but I have read a Russian report to higher authority summarizing the American report.
One of the more interesting comments in this summary was a atatement in the American report that “the designer of the air cleaners (on the T-34)should be tried for treason.” Overall the Aberdeen people were very impressed with the Soviet designs, but found Soviet engines and transmissions to be rather poorly manufactured when compared to American machinery.