The book is titled CHEVROLET POLICE CARS by Edwin J. Sanow.
Here are a few quotes from the book:
"One of today's most cherished muscle cars, the 396-powered '69 Chevelle, was available from Chevrolet to do some official stoplight Grand Prix ticket writing. The Chevelle had been absent from the formal lineup of Chevrolet police cars for a couple of years."
"The Chevelle was available with the B07 police package only in the 116-inch wheelbase four-door sedan."
"The Chevelle 300 Deluxe was available in powertrains ranging from the Turbo-Thrift 250-cid Six for detective work up to the Turbo-Jet 396-cid V-8 for the most aggressive freeway pursuit duties."
"The full-size Biscayne and Bel Air got two-barrel carburetors and merely 9.0:1 compression on their 396-cid big-block engines. However, in the Chevelle, the 396 came with a Rochester spread-bore four-barrel carb and the full 10.25:1 compression. Instead of a 265 hp rating, the Chevelle's Turbo-Jet 396-cid V-8 pumped out an honest 325 hp."
The 1968 portion of the book discusses the possibility of 1968 Chevelle police cars.
"...no mention whatsoever is made in 1968 of any other Chevrolet models being available with police options. This does not mean a police-equipped Chevelle or Chevy II was impossible. It does, however, mean they probably did not exist."
There is no mention in the book of the possible quantities of the 69 Chevelle police cars.