Cleaning up version history document. I also compared it to truecrypt.org and found this important note:
Note: TrueCrypt 4.3a and 5.1a have been repackaged to contain the latest version of the TrueCrypt License introduced with TrueCrypt 6.0 (the original application and driver binaries of those old versions have not been modified; however, the installer used for those new packages was compiled using the source code of TrueCrypt 6.0, not TrueCrypt 5.1a).
This explains why the md5 hashes fail on both "TrueCrypt Setup 4.3a.exe.sig" and "TrueCrypt Setup 5.1a.exe.sig" (the only files which fail). My theory is that whoever first collected these files managed to find everything for 4.3a and 5.1a except the .exe.sig files, and went ahead and downloaded these files from the past versions section on truecrypt.org, ending up with .sig files for the new version instead of the old version. Right now 7.0a, 6.3a and 5.1a is available as past versions for Windows, while only 7.0a and 6.3a are available for Mac OS X and Linux.
I will rename the files and document this in a later commit.