If the system for tool tokens was anything like my former employer P&W Aircraft, the number on the token is specific to the employee who would be issued a number of identical tokens that were kept by the employee to be used as long as they were employed there.
Just guessing but the letters may be to designate a group or department.
Or maybe the 'FB' could be the 'Ford Barn' division of the Ford Motor Co.
They were commonly called 'tool chits' not tokens.