A B737-300 WAS DISPATCHED IN NON COMPLIANCE WITH A DISPATCH RELEASE NOT APPLICABLE TO THE ACFT.

Narrative

2 B737-300'S FROM OUR CARRIER WERE SCHEDULED TO BE ON THE GND IN LGA AT THE SAME TIME. ABOUT 3 HRS PRIOR TO THEIR ARR; A ROUTING CHANGE WAS SENT BY THE OPS CTL CTR TO SWAP THE ROUTING OF THE 2 ACFT OUT OF LGA TO SEND 1 ACFT TO A MAINT BASE IN ORDER TO REPAIR BOTH AUTOPLTS THAT WERE INOP. APPROX 10 MINS AFTER GATE DEP OF MY FLT; I WAS ADVISED THAT LGA PERSONNEL HAD LOADED THE 2 ACFT IN ACCORDANCE WITH THE ORIGINAL ROUTINGS; AND NOT THE MOST RECENT ROUTING CHANGE. SINCE THE COMPUTER SHOWED THE MOST RECENT ROUTING; BOTH FLTS WERE RELEASED WITH THE WRONG ACFT. AT THIS TIME; THE OTHER ACFT WAS STILL ON THE GATE AND ITS FLT RELEASE WAS AMENDED TO SHOW CORRECT ACFT BY THE CTLING DISPATCHER. HOWEVER; MY FLT WAS ALREADY IN LINE FOR TKOF. I THEN ASKED THE CREW OF MY FLT TO VERIFY WHAT ACFT THEY WERE IN VIA ACARS AND UPON CONFIRMATION; IMMEDIATELY TOLD THEM TO STAND BY FOR AN AMENDMENT TO THEIR RELEASE FOR THE CORRECT ACFT. AFTER CALLING CENTRAL LOAD PLANNING; I RECALCULATED THE FLT PLAN WITH CORRECT ACFT SO THE AUTOMATED WT AND BAL WOULD BE CORRECT. THEN I SENT AN AMENDED RELEASE VIA ACARS TO THE FLT; ONLY TO FIND OUT THAT THE FLT HAD DEPARTED 3 MINS BEFORE RECEIVING THEIR AMENDMENT. THE 2 ACFT HAD DIFFERENT MEL'S AND AT THIS TIME; IT IS UNCLR WHETHER MY FLT RECEIVED THE CORRECT WT AND BAL FOR THAT ACFT. ERROR WAS DUE TO CAPT NOT READING FLT RELEASE AND A BREAKDOWN IN COM WITH PERSONNEL AT LGA.