Ah got it. Thanks for the information Darth Lars. I've always really wondered about that since the TPM puppet looks horrendous.
RANDOM MEMORY: I actually read an article around 2005 that they used the TPM puppet as a stand-in in ROTS during the Tantive IV scenes, but it's face was half-melted off, due to improper storage. Apparently the actors had a hard time concentrating because of this.