There's a "TrueCrypt Foundation" key on the keyservers from 2004, the ID is E3BA73CAF0D6B1E0.
The only way to verify is if you have the previous key stored somewhere, or can find a trustpath to it.
E3BA73CAF0D6B1E0 C5F4 BAC4 A7B2 2DB8 B8F8 5538 E3BA 73CA F0D6 B1E0
Checks out.