From the North West Historical Association:
"As the war ended the Allied armies overran the test sites for both the Maus and E100, where they found the prototypes for each. The single model of the E100 was left half-finished at the Henschel test plant at Haustenbeck. British troops(?) occupied the site in May 1945 as the war ended, finding the partially-built hull and suspension." While Pravda has several good articles on the Soviet's obtaining both a V1 and V2 model of the Maus none is supported by source information.
Technical specifications and blue prints: The German Mouse, Super-Super-Super-Heavy Tank Became Hitler's White Elephant
http://www.lonesentry.com/articles/maus/index.html
So far I have found no record in CAMHQ records but there may be some recorded information in some of the US archives as there was a race on to seize and remove German technology prior to the Soviets arriving, Cooper in Death Traps points to several archival sources from late 1945 and 1946 that now maybe internet accessible. The hunt is on.