Okay, so I got this (now well out of print) book the other day, and have been mining it for build info pics!
I scanned & enlarged the pics as some are really small.
Large scans in my Photobucket album here:
http://s84.photobucket.com/albums/k22/Coz_UK/Puppet%20Building%20Etc/Art%20of%20the%20Muppets%20Scans/Some images I found really interesting:

Balsa or hard foam palms? Hard mouthplate which encloses the hand?!

Fingertubes! Eye mech! Reticulated foam!

Think that's the only foam chin pattern I've seen!
Hard to believe the book is 32 years old!
C.