I couldn’t find any evidence that any parts of the U-505 on display at the Museum of Science and Industry, which we didn’t go to, were used in U-571 (from my internet searching). I did see that it was an inspiration to the director/writer somebody (see how close I read). Oh yeah and I did find this quote about it from Roger Ebert’s review:

In case you’re wondering, the German sub on display at the Museum of Science and Industry in Chicago is U-505, and it was boarded and captured not by submariners, but by sailors from the USS Pillsbury, part of the escort group of the carrier USS Guadalcanal. No Enigma machine was involved. That was in 1944. An Enigma machine was obtained on May 9, 1941, when HMS Bulldog captured U-110. On Aug. 23, 1941, U-570 was captured by British planes and ships, without Enigma. This fictional movie about a fictional U.S. submarine mission is followed by a mention in the end credits of those actual British missions. Oh, the British deciphered the Enigma code, too. Come to think of it, they pretty much did everything in real life that the Americans do in this movie.