This is the rarest prize a 15GP22-based NTSC vintage color television set collector can acquire. The legendary Model 5, the "Rose Bowl" set.
Model fives were never sold to the public. Two hundred or so were built just to demonstrate the January 1, 1954 NTSC color broadcast from Pasadenia, California, famous for its Rose Bowl and annual Tournament of Roses parade.
There is an excellent first-hand account of that initial country-wide colorcast on Ed Reitan's site.
The most obvious characteristic of a Model 5 is the diamond-shaped wood design in front of the speaker grill cloth; on a CT-100, the wood filigree is vertical and horizontal.