As long as the final decree authorizes the QDRO, it can be done later... even 19 years later.  In fact, many plan administrators for retirement plans will not act on a divorce decree alone... they will usually require the QDRO.  However, before you go to the expense of having a QDRO drafted, contact the plan administrator to see if the decree will be enough.... on the off chance that they will honor the decree as written.