Mike, If I were looking for and old book I would try the manufacturer and see if they could direct me to an after market kind of company that might specialize in their brand. Just like Plastic Machinery Corp did for Reed-Prentice many years ago.
A search of the Internet on Google or similar might turn something up.
Last, but not least, you might try the Plastics Museum in Leominister, MA to see if they have historical records or how you can access historical documents such as you are looking for. Good Luck! Bob