Yes and I was surprised to see that (along with certain other things about Richard's behavior), considering what I've heard about him on The MuppetCast and elsewhere (including the same book). I keep reading that he was generous to other performers (such as asking off on David Rudman's first day just so Rudman wouldn't have to do a right-hand), and then saw that he would snap at performers who complained about only doing right hands. Of course it's also odd Richard said he did right hands for 8 years, when he did do voices early on (he did voices in The Great Santa Claus Switch, and was one of the main performers in 1974's The Muppets' Valentine Show). He could have been exaggerating, or Robinson could have been misremembering (as he wasn't there when Richard Hunt was just a background performer). There's been a number of Martin Robinson voices that I initially assumed were Richard Hunt's, it's a wonder Marty didn't take over any of Richard's characters (well, besides Old MacDonald). I remember long ago, before I knew the name Martin Robinson and before I knew which Sesame Street characters Richard performed, I assumed that Richard performed Mr. Snuffleupagus (and I later learn he did, but never the voice, just the back half and eventually the front half while lip-synching to Jerry Nelson's vocals). That sketch is in Old School Volume 1 which you said you have (it's in episode 276).