Surely the body should have the jaw number stamped adjacent to the slot???
AWEM
10" Bison self centering chuck that I bought new 5 years ago. Never used the reverse jaws until today (see digger post), and was suprised to find that although the jaws are numbered 1,2,3 the chuck body is not. putting them in in sequence and catching each in turn in the scroll they centered adequately for the job in hand, and the standard jaws went back in a similar fashion. But there is a one in three chance they are in the right slots.