how to find age of my Billy Cook saddle?

Hello everyone!
I`m interesting of my saddle age. It`s a used Billy Cook ProReiner saddle(Greenville, Texas), with silver.



I have numbers -

917(0?)499

8950

Maybe someone know how to get it`s age?

Ps sorry for my english

First two digits of serial number are the year - 1991

Thanks a lot!!!