A B737-200 WAS DISPATCHED IN NON COMPLIANCE WITH THE CAPT'S COURSE SELECT READOUT ON THE AUTOPLT CTL PANEL INOP DEFERRED PER THE MEL. MEL REF USED WAS B737-300 EFIS SYS PROC.

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ACFT ARRIVED AT ZZZ. THE FLT CREW MADE A LOGBOOK ENTRY STATING 'CAPT'S COURSE WINDOW ON AUTOFLT PANEL DOES NOT SET COURSE CORRECTLY. INFLT COURSE NUMBERS OCCASIONALLY JUMP.' AFTER TROUBLESHOOTING; I DETERMINED THE PANEL WAS DEFECTIVE. THE PANEL WAS NOT IN STOCK AT THE STATION SO THE ITEM HAD TO BE DEFERRED. IN THEN WENT TO THE MECHANICAL DISPATCH MANUAL; MEL SECTION; INDEX; FOR CHAPTER 22. FROM THE INDEX I FOUND 'MCP WINDOW; COURSE 22-00-16C PAGE 104.' TURNING TO PAGE 104; I READ THE MEL; DETERMINED IT DID NOT REQUIRE DISPATCH APPROVAL. THE PAGE 104 COLUMN HDG STATED: MCP WINDOWS (EFIS-300); 22-00-16C COURSE. I MISTAKENLY APPLIED THIS MEL (22-00-16C) T THIS ITEM WHICH IS MEANT FOR A B737-300 ONLY; AND COMPLETED THE PAPERWORK; DISPATCHING THE ACFT WITH THE ITEM DEFERRED UNDER THIS MEL. THIS WAS CAUSED BY MY INATTN TO THE DETAIL OF THE MEL WORDING. THIS WAS COMPLICATED AS WELL BY THE INTER-MIXING OF -200 AND -300 MEL'S INTO 1 BOOK. ALSO; I FEEL THAT THE HDGS USED FOR DIFFERENTIATING ACFT TYPES AND APPLICABILITY SHOULD BE MORE CLRLY DEFINED. A CHANGE REQUEST HAS BEEN GENERATED TO TECHNICAL PUBS TO CHANGE THE HDGS FROM '-200' OR '-300 ONLY' TO '-300 ONLY.' THIS WILL ELIMINATE THE AMBIGUITY OF THE 'EFIS-300' HDG AND PREVENT FURTHER EVENTS LIKE THIS IN THE FUTURE.