That is both great and sad to hear. First, for spotters down there, they will get a chance to photograph the 738. Unfortunately, that means the 727 are really on the beginning of the end in AA colors. What a shame.
Although DFW is their largets hub, AA found greater efficiencies by flying the 738 out of ORD and MIA to points all across the US. ORD doesn't prefer 727 flights there so the 727s went to DFW and the MD-80s due a good and efficient job in flying nonstop to most points from DFW. So therefore, a narrowbody that is designed primarily for long hauls was not that needed at DFW.
AA seems to have been replacing 727 with 738 one hub at a time. ORD was completely doneby end of 1999. At 9/11/01 MIA was halfway done, and DFW not touched. I am guessing on Dec 15 if 738 is going to DFW, then MIA is completely done.
Well, I recently checked for flights from Dallas to Dulles, in January, and found that ALL have been switched to 727s. That should have been a clue, that fleet ops were changing, because until recently, several had been upgraded (or dowgraded I suppose) to MD-80s.
But, bottom line is, there is STILL a chance to fly the 727 on AA, get in while you can!